Requesting New Build Ideas.

Well it's coming to that time of the year again. The time where I realize my system is getting to be a tad under powered and I look at spending several hundred dollars again on a new machine just so I can play a game at something better then 10 frames per second. In this case it's Warhammer Online, a game I have a love/hate relationship with.

So I'm looking at parts online and I'm oh so lost. I'm looking to keep the total costs under $500. I'm looking at something mid-range to be more conservative with my money. So far I've been looking at the following components.

Video: GeForce 98000 GTX+ (i.e EVGA GeForce 9800 GTX+ 512MB )
Chip: Phenom II X3 (i.e. AMD Phenom II X3 720 2.8GHz )
Motherboard: AM3 slot Board (i.e. ASUS AM3 DDR3 AMD 790GX ATX)
Memory: 4GB (~$40) (i.e. G.SKILL 4GB 240-Pin DDR2 SDRAM DDR2 800) (I happen to have this already, so a little recycling)
Powersupply: (No idea if I'll need a new one to fit the new motherboard)

The examples are ideas of what I might get to fit the 'need'. Not exactly what I'm planning on getting. Over all, someone give me a clue as to what I should be looking at, for the best cost savings / performance ratio.

So what do you guys think? Give me some ideas, would yah? I really would appreciate it.

If your gonna go with AMD i would get a quad core, they are really cheap now a days. I'm considering one myself for my second pc.