1 - Kara no Kyoukai
2 - Digimon Adventure till Frontier
3 - Gundam 00
4 - Casshern Sins
5 - Evangelion

1.Macross Frontier
2.The promises we made in our early days(Kumo no Mukou, Yakusoku no Bashou. by Makoto Shinkai)
3.EVA
4.The Twelve Kingdoms
5.Code Geass
6.Nana
7.Mushi Uta
8.Honey and Clover
ugh...too much but I really like them

I gotta say, I only have one but it is the Mushishi OST. I'm completely awestruck at the simple, effective, beautiful, and breathing sounds. A lot of the songs seem to use chorus/flanger, which is nice to help create the mushi glowing effect.

In the end - Ost Final Fantasy
Elavation - Ost Final Fantasy
Blue bird - Ost naruto
Get over - Ost hikaru no go

Current List: :)

1: Dragonball Z Japanese Version
2: K-On!
3: Kara No Kyoukai
4: Fist of the North Star
5: Puella Magika Madoka Magi.
:)

list from 2011 anime no particular order:
OS uchuujin - Denpa Onna to Seishun Otoko OP
Kimi ni Gohoushi - Mayo Chiki! ED
oath sign - Fate/Zero OP
Soshite Ima - Chihayafuru ED
LIVE for LIFE ~Ookamitachi no Yoru~ Ben-Tou OP

I am only sure of a top 3 for now:

The Vision of Escaflowne
Mushishi
Rurouni Kenshin: Trust & Betrayal

good topic, i think only in 5 best:

Naruto best hit collecction-----------------> I'm not a fan series

Card Captor Sakura, Character SongBook------------> great anime!!!

Serial Experiments Lain Sound Track Cyberia Mix------------> electronic music everywhere, for an anime, only this

Cowboy Bebop - Vitaminless-------------> fantastic, like a giving a touch of pot xD

Rurouni Kenshin Best Collection-----------> i have to say more???

greetings

FLCL Vol. 3
All of the Samurai Champloo soundtracks
Anything that involves Yoko Kanno

Well, aside from Yoko Kanno, Yuki Kajiura and Joe Hisaishi's compositions...

Horizon OST. EPIC SHIT MAN.

Chihayafuru OST, goes extremely well with the show in my opinion.

Blood C's OST, has a very strong main theme, and i like that one jazz piece.

Sora no Woto OST, especially the amazing grace trumpet solo.

And probably Maeda Jun's stuff..

In no particular order:

Black Lagoon
Darker Than Black S1/S2
Texhnolyze
Serial Experiments Lain
Bakemonogatari