Here is a small list of OSTS I really like a lot.
1. Any OST composed by Yoko Kanno, especially Wolf's Rain and Ghost in the Shell:SAC
2. Mobile Fighter G Gundam
3. Trigun
4. Gundam Wing
5. Gundam SEED
6. Naruto
1. ef - a tale of memories (euphoric fields)
2. A bunch of the Bleach ones
3. I can't really think of anymore but I like a bunch of OPs from some other series.