I accidentally stumbled over this post, so sorry for digging it up again...
An old Atheros card didn't work well in my ASUS WL500GP V1, so I bought a new one which works like a charm.
TL-WN961N -> 300Mbit Draft n 2.0 (new Atheros Chipset)
http://www.tp-link.com/products/product_des.asp?id=138
https://forum.openwrt.org/viewtopic.php?id=20573 <- explaination, why the old one didn't work.
As mentioned in the other thread, it only does B G with the current Openwrt ATH driver. When the new openwrt atk5k is stable, you will be able to switch the card to N.
However since the N standard has been published on October 29 2009 there probably will be non-draft N products shortly.
(The strange thing is that I don't read anyting about "draft-n" on the vendor website anymore - however there is also no recent firmware update available for the card. So it seems as if the card already complies with the final standard.)
lg, Mr.M
Edit: corrected a typo.
(Last edited by mr.m on 23 Nov 2009, 13:39)