as far as BG music goes, anything by Key or Kajiura Yuki (Mai HiME, Tsubasa Chronicle, Erementar Gerad), ones for Rozen Maiden, ARIA, Gundam SEED (Destiny), and Black Cat also turned out well
but nonetheless i like Piano and Violin so meh
oh ya Vocals, Tsubasa, Black Cat, Erementar Gerad had good OP/EDs, ARIA had really good, Rozen Maiden was crazy XD, SEED, Destiny, and Shakugan no Shana (course this is just a few)
Best Vocals in general goes to Galaxy Angel though even though only like 1/100th of em were actually played in the anime XD