After a little research, I decided to buy a TP-LINK TL-WN951N. Others have reported it to work out-of-the-box in Snow Leopard, but for me it wasn't quite plug-and-play to get it running in 64-bit mode. I eventually got it working after fiddling around for a couple of hours, as mentioned in this thread. It was just a matter of finding the right .kext's to make it work, nothing too difficult. I would definitely recommend this card as a relatively simple PCI wireless option for 64-bit Snow Leopard.

Wireless-N networking was the last thing I needed to figure out - my Hackintosh is now fully operational.