Greg, I can confirm that the Buffalo WHR-HP-G54 is very stable under OpenWRT White Russian, which gives you (yet) another option if you go down the path of buying a new router/AP device.
Alternatively, if you're set on using your existing box as your router/AP, why not use a USB Wi-Fi device if you're going to be occupying the sole PCI slot with an ethernet card? USB Wi-Fi dongles are often cheaper than Ethernet ones. (NB. If I've failed to notice that your box doesn't have USB, then please disregard this comment.) Sam
