A little advice please...?

Recently I purchased a book of Legend of Zelda sheet music and I am very pleased with it. However, I noticed that the company who made my Zelda book has also created several Final Fantasy score books.
http://www.doremi.co.jp/Doremi/game-music/sp_ff.html

I'm not at all familiar with the Final Fantasy games or their soundtracks, but I've heard both are phenomenal. Well, since I really love to play the piano, and I'll be finished with the Zelda book eventually, I'm already thinking about the next book of sheet music I want to buy which probably wouldn't be until sometime in the summer.

My question is, which of those books in the links I posted should I get? In other words, what is the best FF soundtrack, in your opinion? Should I go with the "Best Collection" that has score from the whole series, or should I get a book that just features one specific soundtrack? And what about that guitar book?

Well i've only played FF 6 and 7, (and 1,2,3 which I never got far into) so i'm more used to there soundtracks, so I'd say either either the Vii book, or maybe best collection?

Actually, I can get both the Best Collection for Piano and the Guitar Solo book for close to $100 on eBay. Of course, I'm not quite familiar with the music, and considering the difficulty level for the guitar book is "Intermediate" and I don't consider myself exceptionally good at playing it, I''m not sure I'm willing to buy the book without first seeing some scans to find out if I am actually capable of playing the stuff...
Well, thanks for your input and concern!

i'd say go with FF7's. it IS tough at first, i've self-taught myself its OST on piano, but once you get you've got it. and it's a beautiful soundtrack.

Well, after some serious thought, I've figured out that I can get the FF 1, 2, and 3 book, The FF VII Advent Children book, and the guitar solo book for about $140, including shipping!! That way, I get the tunes I love from the original game (the GBA remake of which I've been emulating on my PSP, and I'm ADDICTED to it), some more original stuff, ONE-WINGED ANGEL, as well as some other great stuff from FF VII (Tifa's Theme) and all the guitar stuff as well. Oh, btw:
http://www.squareenixmusic.com/series/finalfantasy/sheetmusic.shtml
http://www.squareenixmusic.com/sheetmusic/originalscore/ff1-3.shtml
http://www.squareenixmusic.com/sheetmusic/originalscore/ff7advent.shtml
http://www.squareenixmusic.com/sheetmusic/nonpiano/ffguitar.shtml

Neat!I need to practice with my ocarina... anyways! Hope you have a good time learning some great FF music!