I loaded BF2 on my HP - Pavilion Laptop with AMD Turion X2 Dual-Core Mobile Processor RM-70 laptop ($675 at Best Buy 2 months ago) with an ATI Radeon HD3200 Mobility integrated graphics card, and 3 gig's of RAM. Runs pretty well, but I think some of the occasional choppiness I experience comes from my Vista 64-bit OS. On the up-side, it loads a game in less than a third of the time that it takes my older desktop which has a NVIDIA 7600 graphics card, 2 gigs, and XP. Also, don't use a wireless connection if you can help it - also negatively impacts gameplay.
My advice: Don't be cheap, get as powerful a laptop as you can afford, 'cause the day will come when you want to run the new BF game whenever it comes out, and you won't want to be stuck with a system that can't be upgraded or at the least can't run the game without an upgrade.
If you don't know how to compare the graphics cards of the systems you are looking at, print out this guide with all of the laptop graphics cards out there and how they stack up. http://www.notebookcheck.net/Mobile-Gra … 844.0.html