Anything on the Android market. Can't really go wrong with a HTC.
For gosh sakes just whatever you do, DO NOT get an iPhone. Don't let Apple suck you in as I have seen done to so much of the population. Just some friendly advice:)
It really depends on the kind of features you want on your phone. Again, Android is a good option. They have a good variety of phones but all of them are good. Just do a bit of research. Think about what you will actually use your phone for and then just research which phones will meet those needs.
If you go into a phone store and ask a person who works there they will help you find something that suites you.