The n900 is probably one of the few phones that can 'act' like a phone with a data-plan only since sip,google voice,gvdailer,skype is so nicely integrated.

Anyone here using a hotspot or data-only plan in USA and using the n900 as a regular phone? How's the experience in terms of availability, dropped calls OUTSIDE the house, quality using
- verizon/sprint hotspot or data-only plan on tmobile
- google voice
- grand-central forwarding to google voice

I sort of do that, on Tmobile.
I don't have any coverage at home, but I have WiFi. When I go places, I turn the 3G connection on, and it sort of works with Skype and Gtalk.