I setup a C@C FreePBX system 2 weeks ago now.. I'm using Google voice for my SIP trunk, I have a Dev 2 box for it - I think I've invested around $90 in it so far.

I haven't used it very much though so I'm not sure how the long term sound quality will be. I am planning on trying to use this for my home phone replacement though.

I need to pickup this up, http://www.cl.cam.ac.uk/~rja14/shb10/angela2.pdf so I have some portable phones at home. They are a bit pricey... but We'll see how they work. Though I am disappointed I have to use their basestation and that the phones don't connect directly to WIFI.

The direct to WIFI ones are like $300+ each. OUCH!