I assume you're talking about the Evo's video recording encodings, not what you'd encode other videos you might convert and copy to your phone. As such, on the Evo...
H.263 will only get you up to 352x288 resolution.
H.264 will only get you up to 8000x480 resolution.
MPEG 4 is the only one that can get you up to 720p.
At least that's how it is on my Evo, unless they changed it in the latest update (which I haven't updated to).