I've been going the internet-only plan with VoIP route and Google Voice since I rarely make calls.
However I have not been able to find a VoIP provider that is usable...

Sipgate has good call quality over wi-fi (not so good over 3G but usable for brief periods) and is otherwise usable except for the fact that it makes my phone have a battery life of ~6 hours on 3G.

Sipsorcery is no longer accepting new signups so I can't use that anymore to get TCP access with Sipgate.

I tried PBXes + IPKall which worked well for two days. Then after that I would get "trunk outage" notifications, and when I do what it says to get my trunk online again I get another notification in ~20 minutes.

I heard rumors that Pidgin works with Google Talk + Google Voice on Ubuntu. If I install Ubuntu 9.04 mobile on my n900 will I be able to use Pidgin to call with Google Voice? Or alternatively can I just install Google Chrome with the GV plugin on that?

Are there any other VoIP providers that people use that work?