I'll second the Panasonic phone recommendation, but add that you should probably stay away from their low-end stuff. Then again, if you're looking for a multi-extension system, that's probably not going to be an issue.

I just wish people would make ergonomic phones anymore. The old AT&T/MaBell phones from the 60s were the best design -- easy to hold, never pressed up against your cheek or too far away from your mouth. Everything since then has been the suck.