All my laptops either run nvidia or they're work machines and they have that shitty intel graphics media onboard crap. I've never had an issue aside from retail vendors dropping support after 4 years or so. Then I turn to sites like laptopvideo2go.com and get "hacked" drivers.
I've been "hacking" drivers since the 90's when I found out that the difference between a belkin network card and an expensive linksys can sometimes be a single digit in the vendor id. So you change one number in one text file and ding you have fancy drivers for an otherwise unsupported operating system. Point being, hacking drivers isn't really scary or going to break your computer, so the only issue I've had with nvidia drivers after years of abuse; isn't an issue at all.
I hear lately that ATI cards are "better" but I use laptops like desktop replacements usually, so things like battery life/power consumption and heat don't worry me. I plug it in and use
this thing.
Back to your question though, you're gonna want to check out some of these to make your choice:
http://www.videocardbenchmark.net/The toshiba has video memory is shared with system memory, I have a personal stigma for doing it that way, IMO: dedicated memory > shared memory. The other two seem to have dedicated memory, but the nvidia one is not available currently at newegg. That leaves the asus K70AB-X2A. I've been an intel guy for the last 5 years, but heard only good things about AMD processors, I just like the intel. I have no valid argument as to why.
Since this is a retail system though, you can probably find it at local retailer and take it for a test drive. Bring a game disc of some quick and dirty FPS (crysis demo!) that doesn't take 45 minutes to install, and see if they'll let you install/play it. As long as you look really committed to buying it, you can talk a sales person into letting you toy with it outside of the rack especially if you act interested in their service plan or warranty.
