Gotta second the other two votes for the T42p, currently probably the best laptop you can buy from a reputable maker if money's no issue and you don't need a ruggedized notebook.  You can get up to a 128MB Radeon (the FireGL is apparently a 9600 of some sort with special workstation-class drivers, instead of the 64MB Radeon 9000 available on the 600m); the performance is awesome; it's more light-weight for the features; it's got a better screen; the keyboard is the best you can get on a laptop; it's more durable than the 600m; it's superior in pretty much every way.  I'd have to check, but I'm pretty sure you have a better choice of drives; if you buy a 600m you may want to upgrade the hard drive afterward.  Also, black is still the best color for a notebook, even if some people claim that it's stodgy!  It minimizes glare.
By the way, the screen on the 600m is NOT the UltraSharp advertised for other Inspirons such as the 8600.  It's decent, just not the best you can buy.