Definitely as a TV series. I love the new Star Trek movies, and I think J.J. Abrams has done a magnificent job of making some fun and exciting Star Trek, but the small screen is where it really belongs, as well as an occasional movie to hammer out some idea.
On the small screen, you can take your time, over the course of a couple of episodes, a couple of seasons even, building up to something great and awe-inspiring. On the big screen, you have about a 120 minute block to go from scratch to conclusion, and make it all work. That's a tight fit, and a lot gets left on the cutting room floor because of it.
TV is where Star Trek started, and I think that's where it works best. Just my two bits.