I would be leaning towards Tokyo for 2016
I am Biased tho... I'm hoping Toronto gets another crack at it, if Vancouver 2010 goes well down the line. Toronto arguably has had some of the strongest bids in the last 20 years, but politics and bribes have kept the Summer Games away for the time being (1996, 2004, 2008 Bids)
On July 10, 2007 it was revealed that the Canadian Olympic Committee had begun work on a potential bid for the 2020 or 2024 games for Toronto