I've already explained my Russell and Erving picks. Russell to me is clearly the defensive GOAT, he's also likely a top 3 rebounder of all-time, good passer, playmaker and ball-handler for his position, and a decent scorer for his era, that year, especially in the playoffs ('62). Also, for what it's worth, he had arguably better intangibles and basketball IQ than anyone else in NBA history. He suffers a bit if we go with "time machine" approach, but every player has a weakness (if not in terms of skillset, then at least in terms of performance at some point of a season). Russell's scoring is a relative weakness, but he more than makes up for it in other areas. I see Russell as a slight positive on offense (if I was forced to use the SRS approach that SSB uses, I'd say he's between +0.5 and +1.0 on offense that particular year, although that +1.0 rating would be based more on the playoffs - in the RS, he was about neutral).
Russell's era-relative impact was just huge. He was a real outlier in terms of his defensive impact. Even though I generally believe that great offense beats great defense (because a great offensive player can dictate the way the game is played, and a great defensive player can only react to the moves the offensive player, and his possibilities of "dictating" the game are limited, even someone like Russell, who seemed to literally change the mindset of offensive players because of how smart he was on defense, still couldn't rival star offensive players in terms of dictating the way the game was played), I think that Russell's impact on team defense was big enough that the "great offense > great defense" (which is mostly about individual offense and defense, not about "global" impact on offense/defense) argument doesn't necessarily apply to him.
Erving behind Russell because even though Doc was a great offensive player, he wasn't really an all-time great playmaker/facilitator (he wasn't even a particularly impressive playmaker compared to other wings of a similar caliber, like Jordan, LeBron, Wade, Kobe), so his overall impact on offense wasn't as high it could be if he was an elite scorer AND playmaker (such as Magic and Bird, although he seems to have the edge on defense over those guys). Russell's global impact on defense was definitely higher than Erving's global impact on offense, IMO.
I've decided to go with Bird as my third pick here, to continue the theme of voting for players who stepped up their game in the playoffs.
Bird is a uniquely talented offensive player because he can make the same impact as elite on-ball players (Jordan, LeBron, Magic, Nash) as a primarily off-ball player, which makes him extremely valuable. That is not to say that Bird was not a great on-ball player/playmaker - he sure was. He was an excellent ball-handler for his size and most likely a top 10 (maybe even top 5) passer in NBA history. Contrary to popular belief, he wasn't a point forward in the same sense as guys like LeBron or Pippen, who often acted as the primary ball-handlers of their teams, but he was a point forward in the same sense as guys like Garnett (in the early/mid 2000s) or Webber (in the early 2000s). Big forward with excellent ball-handling and passing skills (but Bird was better than Garnett and Webber in both areas, plus he was a better outside shooter, who could stretch the floor much better). He could still run the pick & roll as a ball-handler very effectively (especially with Parish as the roll man), but he could also set good screens and be the roll man himself (even more so as a pick & pop guy, than pick & roll). He also had something in common with '14 Kevin Love, in terms of his great outlet passing and being able to accumulate a lot of assists solely as a passer from the post, at times, without acting as a perimeter player. He was also a great cutter who could finish very well with his vast array of close range shots, incredibly soft touch. Just an amazingly versatile offensive player.
Defensively, I think Bird was a clear positive.
[youtube]https://www.youtube.com/watch?v=KpEAZMT5t_U[/youtube]
I know this just a highlight video, but he was very disruptive help defender in most of the games he played during his career, before his ailing back robbed him of his mobility.
Bird was certainly a flawed 1 on 1 defender, especially on the perimeter, where more athletic, quicker players could really give him problems, but he was an excellent team defender, below average/poor 1 on 1 defender on the perimeter, about average 1 on 1 defender in the post, so overall, he still seems to be a clear positive.
Why Erving over Bird? So, first of all, Erving has a clear edge in terms of advanced numbers (in a weaker league, so I wouldn't take those numbers at face value, but his advantage is big enough that even after making a reasonable adjustment, Erving would still come out on top in that comparison), comparable scorer, slightly better rebounder (most people would think that Bird was a better rebounder, but per 100 possessions, Doc looks slightly better - well, I guess we can call it a wash, both were GOAT level rebounders at SF), worse playmaker, but but better ball-handler, better defender (not a big gap, but noticeable in Erving's favor), and (this will be perhaps the primary argument for Dr J) - he seems more likely to vault a mediocre/average team into title contention, a team led by '76 Erving seems more likely to pull an upset win over a stronger opponent. Bird's '86 Celtics team was arguably the most stacked team in the 3-point era.
I'll put it this way - Erving is more likely to turn a weak team into a good team, and an average team into a great team, but is more likely to turn a good team into a historically great team. Both possibilities sound great, but ultimately, Doc's capabilities seem to be a little more impressive to me. This is about the same as LeBron vs Magic - James can help a weak or average team overachieve (like he did in '09), but he's not necessarily a great fit on a stacked team, while Magic thrives on stacked teams, but he's less capable of elevating a weak or average team into title contention due to his inferior motor, athleticism and two-way play.
Erving vs Bird is a very close comparison, and Larry also improved his game in the playoffs compared to RS in '86, but clearly not as much as Doc did in '76 (Bird's PER went down, but his WS/48, BPM and scoring efficiency went up, so I'd say he was better overall in the playoffs than he was in the RS), and Bird had a much better supporting cast around him (on the other hand, Bird's competition was clearly better, too, but I still think that Erving had more of an impact on his team than Bird did, and the Nets would've suffered more without him, than the Celtics would've suffered without Bird - well, we know that the Celtics were still an above average team in '89, without Bird).
Why Bird over Garnett, Robinson, Walton? So, it clearly seems like Bird performed better in the postseason (yes, even compared to Walton). Garnett, Robinson and Walton played at least a little worse in the postseason (I'm talking about '04 Garnett, '95 Robinson and '77 Walton) than they did in the regular season, while Bird played a little better in the postseason. Garnett and Robinson have an edge over Bird based on RS play (but it's not very significant and it doesn't have any kind of an important impact on winning - all of them were worth about 20 wins for their respective teams, in my estimation), not sure if Walton does - honestly, I'd probably go with Bird over Walton for RS, although the way I see it, Walton played closer to his RS standards in the postseason than Garnett and Robinson did. I think the playoff gap is more important, personally.
Why Bird over Magic? Oh, the comparison for the ages...Bird's advantage on defense (both had similar strengths and weaknesses - both mediocre 1 on 1 defenders, especially on the perimeter, but both good team defenders - the thing is, Bird's team defense was more impactful, so he gets the edge overall - everybody except for diehard Laker fans would likely agree that Bird was better defensively, even if it's not a huge gap) is the most important difference between them, to me. Besides, I think that Bird is slightly more portable, because of his superior off-ball play (but the question is - would you really want to take the ball away from Magic's hands? I wouldn't), and shooting ability. It's very close, and as soon as one of my top 3 picks (Russell, Erving, Bird) gets selected, I'll likely have Magic in my next top 3.
Why Bird over Wade? So, I don't think Wade's '06 regular season was as good as BIrd's '86 (Wade shot only 52.1% TS, which is below league average, in 18 games without Shaq in November and early December of '05, and the Heat were only 9-9, exactly 0.500% W, in those games - I mean, sure, he improved his game later on that season, as evident in the playoffs, where he was absolutely fantastic, but in such close comparisons, little details matter), and I'm not convinced if Wade's playoff run in '06 was really better than Bird's '86 playoff run.
Besides, I think that '09 Wade was a better player than '06 Wade. He just didn't prove enough in the postseason in '09 (I'm not talking about team results, I'm talking about his individual play - he was very good, but a little below his RS standards)
Bird was much better off-ball on offense than both '06 and '09 Wade, which makes him more portable. Wade was better on defense, but not to a degree that could sway me to support him over Bird right now.
Why Bird over Curry? Better individual play in the postseason. Especially against tough defenses - Bird had a phenomenal series against a very tough Bucks team, -4.5 defense, and a great series against a very solid Hawks defense, while Curry played a little below his standards against the Grizzlies).