What kind of money are you looking to spend? That will greatly affect what would be your best choice. I know you asked about 15"ers, but I have a 17" Dell Precision 6400. Quad core, LED screen, 1 gig video card, just about the best of everything. And this thing is a workhorse. It can seamlessly rotate the most complex 3D parts, with no screen freezing or stepping, has great color representation (if anyone has yet to see an LED screen, you will never want anything else once you have had one), and also has a numeric keyboard. But to buy this same computer will set you back about $4000. Worth every penny I spent my book, but that may be more than you are looking to spend. It also weighs about 12lbs including the massive 220 watt power adapter. It is heavy, but that is just the price you pay for that much computing power.It is definitely not light, but I carry it every day and don't even really notice the size and weight any more.
