http://sports.yahoo.com/news/ten-greatest-athletes-chicago-sports-history-162900449.html
After some more research, here is an updated version of the list.
Joe Louis

Gordie Howe

Barry Sanders

Ty Cobb

Steve Yzerman

Isiah Thomas

The other 4 positions should be filled out by some of the following. I'll put them in my idea of order of likelihood:
Nicklas Lidstrom - I have been schooled.

Hank Greenberg - 183 RBI in a season? 58 HR? .616 slugging in 12 years as a Tiger? He was Miggy before Miggy was Miggy.

Calvin Johnson - He might end up being the best WR of all time. Imagine if he had Joe Montana and Steve Young throwing to him. In 6 seasons, he has 9 receiving records.

Miguel Cabrera - I've rethought this one. Miggy goes ahead of Verlander. They are both the most dominant at what they do, but we haven't seen Miggy swoon like Verlander is this year. Unless you want to recall his drinking with the season on the line.

Al Kaline - Had an effin' battery named after him. 18x All-Star, 3,000+ hits, announcer for 27 years. He's a sentimental choice to be on the list. It's hard to weigh his long solid career against the current players with higher peaks.

Ben Wallace - Defensive and rebounding beast unlike anything the NBA has seen before. Shaq stopper, Howard stopper....most feared defender in the league for a loooooooong time.

Tommy Hearns - The Motor City Cobra is a legendary boxer.

Justin Verlander - Right after Miggy. He was untouchable before this year. Odds are he'll get back on track soon.

Terry Sawchuk - Given the label of "Best Goalie Ever" at the time, he broke the record for most wins by a goalie, not to be broken for 30 years (by Martin Brodeur).

David Bing - Being mayor doesn't factor in positively or negatively, but he had a great career as a Piston. Averaged 20-7-4.

Alan Trammell - Had a long, great career as a Detroit Tiger, peaking as a runner-up to the MVP (George Bell). His accomplishments can't be mentioned without talking about his other half, Sweet Lou Whitaker. Speaking of which, did you know Lou Whitaker's middle name is Rodman? DETROIT SPORTS!

Fennis Dembo - Led the Detroit Pistons to a championship sweep over the Lakers, hitting every single shot he took for an astounding 100% fg% in the 1989 playoffs.

Bobby Layne - Wasn't a Lion that long, but led the team to 3 championships.

Bob Lanier - Averaged 20/10 over the course of his NBA career, spending 10 years with the Pistons.
That's 18 (+1) players who could easily be in most city's Top 10. Detroit has been blessed with a lot of amazing talent. I'm sure there are more that could be on the list, and I'm sure many people would rearrange the order I have them in, but you have to admit, it's a difficult project.