I wasn't nuts about having to pay $30/mo for data either, but I'm such a disorganized slob I really needed something to offload my brain into. Hence the iPhone, which is great for me because it can be everything: phone, calendar, music player, GPS, instant access to all human knowledge, etc. So I just have to not lose it and remember to put appointments into it, and I'm golden.
When I switched to AT&T from Verizon, I asked for a minutes plan that isn't advertised anymore. So we get something like 550 minutes to share between two phones and I added data for my iPhone, all for about $85/mo, which was about $10 less than we had been paying for just minutes to share between two phones at Verizon. We were able to get away with fewer minutes at AT&T because of the rollover thing- we have periods of heavy usage, but much of the time we're not really using them that much.