Budget peformance laptop?

Ok so im interested in playing newer games like crysis 2 and 1, all the call of dutys and possible mw2, fallout 3 goty and new vegas, battlefield bad company 2, etc are the games i wanna play. If your a pc gamer like me you would know that most of these games either require dirextx 10 or 11 and shader model 3.0-4.0 and a decent cpu and amount of ram. Im looking for a budget laptop that could play most of these games on medium-high settings, nothing realy special. Something simple with a decent gfx card and good processor which is quad or duo with something good like high 2. ghz or low 3 ghz. And the most important part is it needs to b fully upgradeable with nothing Integrated so i can just pop in a new gfx card, processor, or ram. I was interested in a toshiba Satellite but there are just so many different models and laptops on the market im confused. The budget im looking for is about 400 dollars and maybe just maybe mid-low 500s if its something really special. I know this is a very specific and picky request but if any one bought a laptop like this or knows a great website that takes all those choices organizes them that would be great.