Staying with Sprint? Your choices are between the SGS2 (Sprint calls it the Epic 4G Touch) and the Evo 3D. If you had a good experience with the Evo 4G and want to continue it with something with better hardware: Go Evo 3D.
If you want a change, or you didn't really like your Evo 4G, get the E4GT.
Or go into the store and check them both out and see what you want more.
And...of course, the iPhone is also a possibility.