Since no-one's mentioned them yet, I'll throw in the the Hymmnos songs from the Ar Tonelico series Plenty of vocal tracks in those games, which is kind of expected for a game where songs/singing have a fairly central part of the storyline (no nothing to do with pop-stars and such ), and a wide variation in styles too I'll link to a handful below:

YouTube - Ar Tonelico - EXEC_CHRONICLE_KEY/. With Lyrics
YouTube - Ar Tonelico - EXEC_PHANTASMAGORIA/. with Lyrics
YouTube - Ar Tonelico II - EXEC_SPHILIA/. with Lyrics
YouTube - Ar Tonelico II - EXEC_with.METHOD_METAFALICA/. with Lyrics
YouTube - Ar Tonelico 3 EXEC_EP=NOVA/. with English lyrics
YouTube - Ar Tonelico III - EXEC_COSMOFLIPS/. with Lyrics
YouTube - Ar Tonelico III - EXEC_Z/. with Lyrics