If you are not planning on any heavy ocing but simply gaming a high end gaming card seeing a good vpu cooler and something like the Zalman CNPS9700 for an AM2 board with a faster 6000+ or 6400+ X2 3+ghz cpu or 9500 for a 939 board will work quite well.
The newer 6000+ X2 runs stock at 3ghz while the 6400+ X2 runs at 3.2ghz there. Which version of Windows will you be running XP or Vista? The investment in liquid cooling is generally made by those who plan on ocing on a regular basis with water coolers also available for video cards as well as cpus. For those often many go for a full tower when cramped with a mid tower.