dude, how long does it take for video cards to be insufficient? A 6600gt that was bought just a year ago, and handled everything then very well now struggles in new games. Badass gaming laptops will become mediocre gaming laptops in a year. The ONLY reason to go with one, is if you absolutely have to be mobile all the time. If you go to an occasional LAN party, get an SFF system. Laptops are NOT worth it for gaming unless you've got wads of cash and HAVE to be mobile.
For the $5k you spend on a laptop, you could spend $2k on a CRAZY gaming pc, and stash the other $3k for upgrades for the next 3 years to keep it on top. To me, it's a no brainer.
I have a little compact P3 laptop with wireless that I take everywhere. It's perfect for classes, and the coffee shop. I play old non graphics intensive games on it, like ScummVM, and SNES emulators, both of which it handles perfectly. a 2MB Ati Rage IIC is... how shal I say.... insufficient for any sort of hardware acceleration. But, it does handle hardware overlays reasonably well, allowing me to watch SD h.264 video in full screen with media player classic's overlay mixer and the CoreAVC decoder. I can watch any of my archived media from my desktop on the laptop perfectly. I got my lap for under $200, and it does everything I need.
Spend a bunch on a gaming PC, and then get a basic lap. It really works out well.