I have tried to use Virgin's U.S. wifi service when in the air. My BBerry shows UMA (wifi voice) is connected, but I can only stay connected for a few seconds. SMS works ok. Since I take their red eye across country, don't usually bothering paying for wifi. For a few years, there was free wifi around Xmas on Virgin, sponsored by Google.
GoogleVoice (domestic call forwarding and cheap intl. calls)
T-Mobile lines on unlimited "family" plan - me, wife. Cost is about $80 a line incl. 5GB/mo. data on each line. We have had no landline in 7 years