Is it legal for cell phone companies to force you to have a data plan?

Why are cell phone companies forcing you to get a data plan if you want a smartphone? This isn't fair. It seems that all the really nice phones require some sort of PDA data plan. I love my Samsung Fascinate from Verizon and I like having the Internet and Pandora Radio on it. The worst part is that you have to sign a contract. Is it fair that all of the "cool phones" require the most expense and you have to have a contract? Only smartphones. Why no alternatives?