FWIW, I have a Linksys B router at home that I've used with both an Airport card (TiPB) and Airport Extreme card (AlPB) and had no ill effects. I've only upgraded the firmware once in the past year.
All though I must say that I believe my over all connection speeds seems to have decreased a little with the AE on the faster PB... go figure. I first chalked it up to SBC slowing down with more local business, but now I think it might be something with my new set up.
I'm thinking about upgrading to a wireless G router, any suggestions?