The correct question so ask is not what
card to get, but what
chip. One of the difficulties with this is that wireless cards are sold to be pretty generic. It is often not easy to figure out what chip is on what card. if you live in an area with retail computer stores, maybe you can physically check the card. I've had hassles with having to return cards that were sold as chip X (Atheros), but the product that arrived had chip Y (Ralink) on it. The vendor claimed that it made no difference, since both are wireless cards, and both work under windows with the driver CD that's included in the package. The vendor may be right, but that is irrelevant. (To their credit: they refunded my money, and didn't even require me to mail the cards back, so I ended up giving them away to friends who needed cards for their laptops).
I'll join the chorus of people who recommend Atheros chips. I currently use an Atheros 9285, on a no-name-brand miniPCIe card. It works 95% well as an access point, in 802.11g mode. It runs at many Mbit/s (just tested at 4.5 Mbit/s moments ago), and I really don't care whether it should run faster, because I have no workload that requires faster access.
Why do I say that it only works 95%? Because there is a known bug in the
ath driver in FreeBSD, which manifests itself as log lines saying
Code:
ath0: stuck beacon; resetting (bmiss count 4)
The cause seems complicated, and I only marginally understand it: has something to do with having two diversity antennas, a high noise level on one antenna but not the other, which then causes the driver to wrongly disable both antennas, and then trip over its own feet because it can't send beacon packets out, even though it should be able to, since there is a noise-free antenna (I probably mangled that explanation). The effect is that all wireless freezes for a few seconds up to a few minutes. Most of the time, it fixes itself, before any of my "users" (wife and son) complain. If they complain too loudly, I mutter something about "computer problems", and go reboot the server / access point.
I would definitely buy the same card again (even with that little glitch). And I continue to believe that for simplicity of system configuration and administration, and for power efficiency, having a small home server also act as the wireless AP is a good setup.
