Yea, you're going to get a ton of responses here with plenty of opinion with an open-ended question like that.
If you have the Sprint TouchPro, I would seriously recommend Ivan's 1.8 Black. It is faster than anything else I have used, and has some nice interface upgrades that dont waste space. I would also recommend using TF3D config to remove excess pages (I dont personally use the calendar or settings tab).
Good link reviewing all the ROMs here:
http://sites.google.com/site/ppcgeek...Sprint-ROM-1.8