GTX260 water cooling block

Ek block
http://www.frozencpu.com/products/78...0_GTX_SLI.html

Aqua Computer aquagraFX for nVidia GTX 280/GTX 260
http://www.sidewindercomputers.com/aqcoaqforgtx.html

dd waterblock
http://ncixus.com/products/productde...er=1&sku=33873

Just make sure that you get the right block for the card. The 55nm version and 65nm version of the card will use different full cover blocks.

Another thing you can do is the D-tek Fuzion GFX block with the little unisink kit as well.

Block: http://www.dtekcustoms.com/index.asp...rodID=222&HS=1

Unisink: http://www.dtekcustoms.com/index.asp...ROD&ProdID=223

Both of those are very very nice as well, some people prefer the EK block listed above or whatever, just personal opinion really, but I really like D-Tek ^.~