I switched over to Mobilicity thanks to their 1st anniversary deal. It was $40 per month + tax, for unlimited minutes, unlimited data, unlimited global text messages, unlimited long distance within North America, voice mail, 3 way calling, call waiting, caller ID. No contract.
I've never had data on a phone and I'm sure the novelty will wear out (foursquare is a total waste of time, but I like seeing myself "winning" amongst my friends), but that's the deal and it's a fine one.
Biggest problem with Mobilicity is their zones are a bit small.. the northern border is just 2 blocks north of me and I often find myself in "roaming" depending on where I am inside my own house. But I can't complain with that price, and I got myself my first smartphone.