By the way... what do you think the best game I could reasonably run with this build would be? I'm going to build a real gaming rig in one year before I go to University anyway, but this'd be good to tide me over.
Yeah, the myth about PC gaming being really expensive is so very, very wrong. My desktop was $300 in 2005, if I remember correctly. Or, at least, my dad bought something near-identical last year for $300. I told him to ask me, but he just looks at price and never at performance. Anyway, I threw a $70 graphics card in it last summer, the 1gig DDR3 5670, and I can play Crysis, crysis 2, Metro 2033. All on lower settings, of course, but they still look better than the console versions.
A $300 build gets you a lot further now than it did in 2005, so if I'm playing new stuff with my 7 year old hunk of junk, just think what your build will do.
Oh, and I play games in 1440x900 or 720p. The former because that's what my monitor is, the latter because my 1080p TV doesn't get along with 1280x800 and letterboxes it when I have it set do duplicate my monitor.
Steam sales. There are at least 9 every week, including mid week madness and weekend deals.