G3 iPhone - To have or not to have?

So I may be getting an iPhone for Christmas but my only concern is that I do not want to pay for internet twice (internet for my home computer and internet for my iPhone). The main functions I want for my iPhone are: phone, e-mail (internet), calendar, and music. I have heard mixed reviews from a number of people and I haven't really made up my mind yet. Overall, I love it, having multiple functions in one little device. Anyhow, what do you all think??