Who is the best service provider for the iPhone?

I'm looking into getting an iPhone, but I'm really not sure who I should go through. I've heard some different things about different carriers and I'm not sure which one I should go with. As of right now, I have a TracFone and I do like the whole prepaid thing, but I do feel like it's time to get a phone with an unlimited everything plan since I do text and call a lot. Suggestions would be great!

Added (1). I don't necessarily want unlimited *everything*. I do for sure want unlimited talk and text though. I'm also looking for the cheapest plan. If I understood correctly, Verizon was $90/month for any smart phone and I don't have that kind of money. (I'm only in high school!) I have yet to look into AT&T.

Verizon is good apparently.

Get Verizon or AT&T. Best companies. Verizon is a little more expensive, but they get better signal.

Very few places have unlimited everything. Phone calls and texting yes, but not data. Then you have to decide if unlimited everything is more important then good coverage. For me it is coverage. I want my phone to work everywhere. For that it is Verizon or AT&T. Verizon has the better customer service and AT&T is about $10 cheaper a month. Sprint is unlimited, but their customers are not very happy and don't stay long.