Well, I'm a HardCore gammer, and I can give you an over-view of what WE like, I guess...
Well, The internet will have to be 56K++ regaudless of what game(Maybe StarCraft, and simaler RPSes)
-The Machines rite now we need is about 650MHZ(this is the min for most game rite now...)
-256RAM+, if you're a gammer, you need this, NEED...
-For RPG's MMORPG, and shooters, anything new rite now, we need a 32mb video card to be able to see what you're doing, cuz anything lower you'll have BAD game-play...
-20gb+ HD at bare MIN...++
-32X+ CD-ROM
For like the internet for shooter games(Counter-Strike), as you prolly know, you need a HIGH-SPEED ISDN, or cable++
And you said you've ADMINed a CS server, why don't you get about 3high-end XP1900 512ram CABLE/T1++ and rent out some (dedicated) servers for CS... that will work...