I'm going to look at the E90 M3 when it's out.

AFAIK, those of us who took the 179 deduction need to keep the X5 for five years unless we want to give some money back to Uncle Sam. That will be about right for me if the M3 works out... it will have been in production for about two years. Of course, those of you who are familiar with my posts know I kept my E30 325i for fifteen years...