There are inumerable possibilities for this one, mostly because of taste, but some animes just stand out above the rest. Share what you think they are and why. (And who wrote it composed it if possible)

My personal favorite has to Escaflowne, Vision of or the Movie. I love Gregorian Chants, and that combined with Yoko Kanno's melodies is magnificient. It just blows me away every time I listen to it, including right now. Soras Folktale and Black Escaflowne are some of my all time favorite peices of music bar none. The opening is also really good, its called Yakusoku Wa Iranai. There are lots more, but I cant remember them right now.

Other honorable mentions are Wolfs Rain, also done by Yoko Kanno
Much of the music from Bleech, [(the changing themes are neat) Precipice of Defeat, Asterisk, Number One, Battle Ignition]
White Reflection from Gundam Wing Endless Waltz
Crual Angel Theorem from EVA
Anything from Cowboy Bebop but specifically Rain, Green Bird(Where Spike falls through the stained glass window) and that credit song, I cant remember what its called...

Any anime where Yoko Kanno has been involved as soundtrack/music composer wins in my book.

Wow, first thing that came to mind was exactly what you guys wrote. I was especially impressed with Wolf's Rain's music. Too bad the plot didn't back it up. But yeah, Yoko Kanno has endless talent. Is Yoko Kanno a guy or a girl? I never bothered to look it up. >.> I mean, I'm thinking girl but I dunno. And how is he/she so good? I can't believe I'm able to say I have a favorite modern composer and they're actually alive.

It seems difficult to find good music in anime.

- Amy.

Music?

FLCL had a soundtrack done entirely (almost) by The Pillows
Cowboy Bebop and Samurai Champloo both have awesome themed soundtracks. Jazz for Bebop, and Hip-hop for Champloo

That's all that immediately comes to mind

Other than the ones already mentioned, I'm a huge fan of Yuki Kajiura's soundtrack for Noir myself. The opening theme Coppelia no hitsuki is very cool, and I especially love the song in the background for a lot of the fighting, Salva Nos, with its fast electronic beat and latin lyrics.

Out of Yoko Kanno's work, I'm quite fond of the soundtrack to Ghost in the Shell: Stand Alone Complex myself. And I'm a huge fan of Joe Hisaishi's beautiful music for Miyazaki's films.

Yoko Kanno's music is wonderful. so wolf's rain is most deff one of my favorites.
Im also a HUGE fan of the AIR music.
the background music, the opening, the ending.
they are all so peaceful and relaxing, that which makes it real good.

I like the music for Le Portrait de Petite Cossette by Yuki Kajiura best. I haven't even seen the anime, but I found the soundtrack on sale last week and fell in love with it. If you had asked me before then, I would have said the music from Cowboy Bebop by Yoko Kanno. A couple of others high on the list would be the music for Haibane Renmei and Ghost in the Shell: Stand Alone Complex.

For me:
Loveless (the best XD)
TRC (so sentimental -_-,)

FLCL for the fans of course it great plus it features the pillows. Great soundtrack. That's on the light hearted side, but the true taste is the soundtrack of Elfen Lied. I know most of the soundtrack is more sympony music but I still think if fits with the series perfectly, sorry don't know the composer. I think that when the music supports the story I normally seem to be more involved with the action.

I agree with ShiNN, anything by Yoko Kanno, Cowboy Bebop, Macross Plus and Ghost in the Shell are a few that I can think of right now. Trigun has a good soundtrack, Hellsing, Bleach, just to name a few.

Everyone loves yoko kanno. i also have a liking for taku iwasuki's music. i loved the soundtrack to witch hunter robin. i was suitably dark and matched the series very well. i'm a fan of noir's music, and i abolutely loved the music from .hack//SIGN. and, oddly enough, serial experiments lain.

I liked the music from Noir and Madlax. I can listen to that stuff all day long especially the battle themes. .

The gundam wing movie and series takes my cake.

The music to Noir is completely awesome. Sometimes I find myself getting distracted by it, and completely losing track of the plot so I have to rewind...XD

I have to admit that I'm seduced to watch a series by the music, some series I don't even like the anime all that much, but love the music. The soundtracks (or song in them) that I'm currently addicted to are Vandread, Tsubasa Chronicles, Suzuka, Ghost In A Shell-SAC and all of the music in the Infinite Ryvius OST. The anime the .hack - series has to be a great combination, great story, animation and music - it takes my cake.