Read the review of various cards on Anandtech.
Their criticism of the MSI heatsink is valid. I have a MSI 6600GT which isn't in a computer yet. When I first looked at it, I was suspicious about the heatsink installation, Anandtech verified this.
I now have the heatsink detached and am sanding down the heatsink surfaces. I haven't seen any 6600 aftermarket heatsinks, and since the MSI heatsink looks nice and is reportedly quiet, I decided to get the heatsink working. The heat sink is copper color coated aluminum, not copper.
If I had known about this problem I would have gotten another brand card. Probably something that throws in a copy of DoomIII. The MSI box has a doom3 logo, but the game is not included. BTW there are a lot of CDs included in the package, but I haven't installed them, so I'm not sure how useful. Here is a brief description (mostly what the CDs are titled as):
WinDVD Creator Plus
CD titled MSI game collection (probably a bunch of free/shareware)
Driver disk
Disk with photoshop album SI and 3d-album
MSI 3D desktop
InterVideo WinDVD 5.1 channel/ Supreme Foreign Language Learning Machine (huh?)
MSI Media Center Deluxe II
Virtual Drive Pro/ Restore It! Pro
URU
Prince Of Persia: The Sands of Time (2CD)
XIII (4CD)
+ HDTV/S-Vid adapater, DVI/15-pin adapter.
I think this is the standard package since it is the one shown on the MSI site. I got mine from NewEgg.
After this sanding, the heat sink looks like it will work fine because it fits well, but I don't think I would voluntarily do this if I didn't have to.
Lapping details available on request.
Hope this helps.