720p vs 1080p

I really don't want to make this choice... But, it does have to be made. If I remember right I said a while ago that we would probably shoot this in 720p. However, I've been working with video, (from the 1D MK IV), and 1080p really looks drastically better than 720p. Some of this may be due to the fact that I'm viewing the video on a real screen, uncompressed from the camera, not a YouTube version on a smartphone. When we're done though, I want to be able to put this in our home theater and show it to friends without being ashamed of it (thought I'm sure I will be able to see / hear flaws)
The problem here is that we can shoot 24 or 30 frames per second 1080p, OR 60fps 720p. The 1080p looks much better, but it only takes 30 fps, so slow motion will be very limited. Right now, I'm thinking we will probably shoot the trailer in full 1080p to get a feel for it, and see if that will be feasible for the whole thing. It's possible that we could shoot the film in 1080p, and switch to 720p for the slow motion parts, but I don't think we'll do that.