You need DSL or Cable internet. You can get by with the video card and ram for a time (do not install Doom 3 you will not be happy). Yeak Ram is cheap (did you say you had 512? cool for now, gig is great though). The Video Card is all you need to consider for gaming, it's more important than your CPU which is decent enough. I'd wait to buy though, NVidia just released their newest card and ATI is preparing for a release. You should be seeing some significant price drops on mid-range video cards soon (check your circulars and get there at once to grab one, they sell out in minutes sometimes). I have a Geforce 6800 something or other and would suggest it as a minimum starting point (you can then attempt Doom 3 at medium setings).

Oh yeah, some(all) of the MMORPG's save your profile (character information) on their server. Of course the game installs on your hard-drive and usually you have a choice of installations (partial, middle, or complete). Complete being the idea, 80 GB is enough, and hard-drives are cheaper then ram, often enough now.

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