I’ve used both. At the moment I use Final Cut Pro. But I was taught on Avid to begin with. Which one you use out of both of those programs is negligible. Final Cut Pro makes up about 49% of the industry at the moment and the rest is Avid, so really it is like half-half. If you go to film school, you should check out the Avid suites they have available to them and see if you like it. Avid is often not easy to use, but with training it is fine. It may be that you just don’t like Avid and don’t have the patience to learn it, in that case just stick with Final Cut Pro. For the sake of the industry it would be good to learn both, but I don’t think it matters much anymore ever since Walter Murch edited Cold Mountain on Final Cut.
When it comes to sound though, Avid Pro Tools is by far the best choice for a dedicated soung editing program. I don’t know of another sound editing program worth a damn and I’ve done 5.1 Surround mixes in Pro Tools.
In my humble opinion, Final Cut Pro is a professional editing program. I think it still has a “prosumer” atmosphere surrounding it though. Avid has always been considered the professional program and is the one film students are trained on, but really there is no easy way to answer a question of which one is better. But I can tell you what programs I use:
Final Cut Pro for picture editing
Color for the grade
Adobe After Effects for titles and basic visual effects compositing
Avid Pro Tools for sound