FF1 - Pretty good. Even better in Origins.
FF2 - I didn't like this one that much. The Origins version was better, but still not my favorite.
FF3 - It's alright.
FF4 - Quite good.
FF5 - Good stuff.
FF6 - I'd say it's pretty good. Not as good as most people claim, IMHO.
FF7 - I guess this one's my favorite FF battle theme. Lots of action, aggressive, sounds nice.
FF8 - I like this one too.
FF9 - This one was good as well.
FFX - I didn't like it. It's too happy and annoying for my tastes.
FFX-2 - Not good, really. I haven't played the game, though.
FFXI - Not bad, although nothing special. Though again, I haven't played the game.
FFT - I haven't played this one much, either. But the battle songs are quite good.

For Laguna's battle theme, my opinion about it is pretty similar to my opinion about FF6's battle theme: It's not as good as everyone claims, IMHO. About Mystic Quest, I don't remember how its battle theme was. Meh.