I have thought about leasing in the past. But, it seemed like everytime I do the calculations, it didn't make sense for me to lease.
It always seemed like after 3 years of ownership, the depreciation on the car was less than what you paid during the three year lease; i.e., you would probably lose less in depreciation versus what you "lost" in monthly payments...especially b/c BMWs tend to keep their resale value relatively high compared to other makes.
Not am not in anyways an "expert" in this area, but just my observations.
'09 e90 AW 335i M-sport
BMW PPK 1 / BMW Perf. Exhaust and Gloss black grilles / 19" BMW 313 Perf. wheels / BMW Perf. aero side skirts and rear diffuser