Keep the LS
10x more luxurious then any of the others.
Either that or the M3, because that's the fastest and best handling of the bunch.
Depends on what you want it for actually, to be honest.
Ooh, that's right... If you're really as much of a baller as you would like us to believe, get the new '07 LS460 or LS460L (Long wheelbase model)
That thing is totally revamped, 380 hp 4.6, 8 speed transmission... 5.5 seconds to 60, and best of all, it's still an LS. ^^