Anime Soundtracks, And Their Awesomeness.
 

Which anime have the best soundtracks, in your opinion?

Of course, FLCL is probably going to get high marks for the Pillows, and the unbelievably awesome credits song, "Ride On Shooting Star." Others I really dig are Cowboy Bebop and Azumanga Daioh (okay, Azumanga's music is totally cute and probably not suited for half the population, but I totally adore the music, even the ambient ditties that play now and then in the series).

What are yours?

Witch Hunter Robin - from Piano (Half Pain) to Electric Guitar (Shell) it's got a great score.

FLCL had a great soundtrack, but Bebop is by far the best. Not only because the songs are great, but the great number of songs.

I also love the first Bleach soundtrack. Second one was good BGM, but not good just to listen to.

Hellsing's was pretty good too

I second FLCL.

Neon Genesis Evangelion's three soundtracks would be in my favourites if half of the songs were not FLY ME TO THE FUCKING MOON!!!

The OSTs of .hack//Sign and Tsubasa Reservoir Chronicle are a must, even if you don't like the shows (especially Tsubasa. God, I hate Tsubasa!).

Cowboy Bebop and Samurai Champloo are, of course, vital in any fan's library.

As for Fullmetal Alchemist (because I know it will get mentioned), I thought only a handful of songs are really powerful apart from the ones with lyrics.

Since Fullmetal Alchemist (the series?) was already covered, I'll say Fullmetal Alchemist: Conqueror of Shamballa - Among it's more... opera-y pieces that I could do without, I quite like a few of the instrumental ones, like Sad Resolution: Separation and especially Requiem. (As well as it's vocal ones too, Kelas and the other ones from L'arc en Ciel)
I'd like to try some of the other many many FMA soundtracks, especially the ones with songs sung by the other characters. Bratja is good, both in Russian and the (unapproved) English version.

Other than the few songs from the FMA soundtracks that I like, I don't really listen to anime soundtracks (mostly because I don't really watch much anime) But I enjoy the music from Trigun and Cowboy Bebop, of course.

Oh yeah... Now that I think about it, I did buy the soundtracks for Sailor Moon and three Pokemon ones when I was younger... Those are pretty amusing when I feel like reminiscing.

one of the coolest moments of my life, was walking into a store, and hearing the FMA opening theme playing. Maybe I'm just a simple otaku, but that was so awesome.

Gad Guard had some awesome urban jazz, and the opening, Boomerang Boogie is still one of the best Ive heard.

My collection is way too large to list and yes, just my 'favorites' are too large to remember off the top of my head and get all down here. Nut let's see what I can get from memory:

Nearly anything done by Yoko Kanno (Macross Plus, Escaflowne, Cowboy Bebop, Record of Lodoss War TV, Arjuna, Turn A Gundam, etc.)
Rurouni Kenshin OAV OST
Urusei Yatsuri Movie 2 OST
Slayers NEXT Sound Bible III
Nearly every Sailor Moon OST (at least the ones written by Takanori Arisawa)
All the CardCaptor Sakura OSTs
Anything done by Joe Hisashi (Miyazaki Films)
Ah! Megami-sama The Movie OST (Shirou Hamaguchi with assistance from Nabou Uematsu)

....the point is I like a lot of them. The list is getting pretty long though but I've run out of time and I need to get ready for work. So bye for now.

Violinist of Hamlin
Devil May Cry

Two not mentioned animes that have nice music.