I’m enjoying this simple SIP phone for the Mac called Telephone.
It handles multiple accounts nicely. It has a very discrete UI. I particularly like that for touch tone entry you just type on your keyboard.
Works well with Gizmo Project, and hence with Google Voice.
As far as I know Google is the only player in the VOIP market still offering any kind of free dial-out. There used to be a few vendors who gave away a few minutes here and there by they all seem to have dried up. So much for free lunches.
Calling 800 numbers is often still free, and that’s what I’m usually calling where I end up on hold for long periods.