I think Sprint offering unlimited was just to entice people to come on over, I never use more than 2gb - however people that do use over 2gb are the ones to blame for any bog-downs.
You don't use over 2GB now, but in the future, 2GB isn't going to last you very long. Eventually, all media will be digital and mobile broadband data will be at a premium. There's new apps that come out all the time that use lots of data. DirecTV just released an app that allows you to watch things on your mobile device, HBO released one recently, as well. In the future all sporting events, movies, music, documents, etc will all be digital and delivered by wireless to wireless devices and that's going to take data.
The wireless companies in mobile broadbands infancy aren't going to make the same mistake the home broadband ISP's made by never going to tiered pricing early on before people became used to not having to watch what they do with their internet and how much they use it. If the home ISP's could see the future, they would have capped home broadband at say 25GB in the 90's and since most people weren't using that much at the time, people wouldn't have cared, like they don't care now with mobile broadband being tiered and capped, but then when the internet became what it is now, 25GB wouldn't last you very long and the home broadband companies could have had different tiered plans for higher prices. They could never implement tiered pricing now because people are too used to unlimited and would throw a fit if they had to watch how much internet they use. Wireless companies aren't going to make the same mistake. They are implementing tiered pricing ASAP before people get used to unlimited and while 2GB may seem like a lot now, it won't be in the future and at that time, the wireless companies have us right where they want us.
If you can get an unlimited data plan, DO IT. You may not need it now, but in the future you will need a lot more than 2GB a month. And instead of paying $30 for an unlimited plan now, you will be paying $50 for 10GB in the future, and that probably won't even last you the whole month, so you'll have to either pay overage costs, or bump yourself up to a higher tiered plan for a larger monthly fee. Or just not use your mobile device until your next billing cycle.
RIGHT WHERE THEY WANT US.