Building a custom PC

Well, you dont judge a graphics card by how much VRAM it has, a 1gig 5450 or w/e wont perform very well at all. >_> and both AMD & Nvidia make wicked cards, nvidia currently is in the lead though.

Also, Windows>MAC for gaming, no competition. 1tb hdd is only needed if you have tones of games or movies, otherwise you can get by with less, but its like $70 for a 1tb, so why not . Ram, unless you have a 1366 intel set up, either go 4 or 8, with 1366 go 6(1366 supports triple channel memory which is 3 sticks, all other sockets currently out support dual channel which is two sticks)