20070725
I'm suspecting that my problems may be due to the updates to the madwifi trunk breaking compatibility with the AR5008/AR5416 chipset, and not because of Ubuntu/Mint Hardy Heron. And yes, my wireless works fine under Windows XP.
I've noticed in the madwifi tickets that AR5008/AR5416 wireless was functioning and had been broken in the past due to updates but the regressions were fixed. Also, in my previous install on 2008.06.22, my D-Link DWA-552 was working with wireless...