Best USB wireless interface with Linux?

["Carlo Nyto" <carlonyto@gmail.com>]

I am looking to choose a USB wireless network interface that works
well under Linux. Research along these lines has been difficult, as
most people don't choose a wireless interface with Linux support in
mind. Hardware compatability lists do not indicate whether a device
barely works and was in opposition to the vendor's desires, or is with
a full and complete driver. I only purchase from hardware vendors that
do not oppose use of their hardware under Linux.

Requirements:
1) USB.
2) External antenna connector. (something either standard or widely
available, antenna interfaces that you can not buy a cable or antenna
for are useless)
3) Complete open-source drivers that exist due to the vendor being
cooperative, or at least not deliberately uncooperative. Drivers that
are hopelessly buggy, missing critical functionality, do not have
source, or do not work with my choice of recent kernel, are not OK.
4) 802.11a/b/g support, of course. Draft 802.11n support would be nice.
5) Must work as an access point, as a wireless NIC, and with tools
like Kismet. Of course, if it has a reasonable interface to the
hardware and good driver support, this will be guaranteed.

I appreciate any advice.