This was close for me--I voted for the Refit/NCC-1701-A, but I also really like the E-model from the later TNG movies. However, I just feel that the Refit/A-model is the "quintessential" USS
Enterprise. The hull design, the "aztek" pattern on the hull, the way the warp nacelles look...it's just good. Damn good. The scene where the Refit is revealed in Star Trek: The Motion Picture remains, I think, my favorite scene in all the Star Trek movies and tv shows that I've seen (it's also just about the only bright spot in that movie, but that's a whole different discussion!). The Refit
Enterprise also marked a transition from 60s-era sci-fi television to more modern movie-making techniques. The TOS
Enterprise didn't look much different than some of the stuff you can see in "Lost in Space", at least not to me. The Refit is a more serious-looking ship, if that makes sense.
And for those who want to relive that scene from Star Trek: The Motion Picture, here it is in remastered glory:
https://www.youtube.com/watch?v=b52b4yORX6U