Well the AMD X2 is still ddr based ($$$$$$$$$$$$$), and most models only have 512k/1meg l2 cache. Core 2's have dd2 (not $$$$$$$$$$), and 4 megs of l2 cache. With the recent price slashing from intel, you can get a 2.4 ghz chip for like 150 bucks, 4 gigs of ram for about 200.
I still play my main character on my X2 box but its just a matter of time before I move completely to my Quad core.

You can get a very good gaming box for under a grand and it will last a very long time.