I went with Flowroute as my main VOIP provider. The call quality is amazing, they support G729, and their customer service outstanding. The past month at Flowroute ran about $1.86 for around 200 minutes of calls. Granted you don't get voicemail, or any other advanced features but you can easily create your own with FreeSwitch or Asterisk.

I'm trying to port a couple DIDs from BroadVoice, which is the worst VOIP provider on the planet, into Flowroute. They keep blocking the requests due to "account mismatch", and refuse to provide any real helpful information. I just got billed another month of service, so I'm sure the ports will succeed this month.