I hate to keep raining (it sounds pretty good other than this!), but I would be cautious about Zalman's claims of quiet cooling. I've used their stuff repeatedly, and it's really not all that quiet. Usually their idea of quiet seems to be "take a regular fan and plug in a resistor so it runs slower and doesn't cool nearly as well."

I did see a review of a video card that performed well in games and had a passive heatsink. Here's a link to newegg, here's the review.

I am the Doctor, and THIS... is my SPOON!