Buffalo WiFI (802.11b) cards look promising. Orinoco chipset, so I shouldn't have to recompile anything, and the same connectors as the Orinoco-brand cards so I can use my existing antennas. And the card has holes in it so you can wear it around your neck. Oh, one more thing. The antenna is flat so you can stick two of them in your laptop and make a repeater.
Buffalo also has cheap-looking but possibly effective indoor antennas that Brian Aker tried out at South by Southwest with inconclusive results.