If you decide you want a 2010 you should wait til the 11's start rolling out. You'll get a better deal on one because they want to get rid of them at that point.
Also you gain a couple months on the model year buying the 11 but it could hurt with milage later down the road because your putting miles on it before the year so in 2013 youll have 2.5 years worth of mileage on a 2 year old car.
Similiar can be said for the 2010 though. Yes the miles would be less at the point of purchase but it is still considered a one year old car.
Man, no offense but what rock have you been hiding under? Wait till the 2011's before getting a 2010 so you can get a better deal?
1. Nobody even knows if there will be a 2011 Si.
2. Chances are if there is, it will have VERY minor changes.
3. There have been so many threads asking where the 2010's are. I doubt that even if he can find one, any "deals" will be made... now or in 2011.
When it comes down to it, unless there has been a significant change, it doesn't matter about the year of the car as much as the miles. Think 2009 vs. 2010 Si's. In 3 years, if you were out to find an Si and you found one that was a 2009 with 30,000 miles on it and a 2010 with 35,000 miles on it would you really go for the 2010 over the 2009 because it is "newer"?