My favourite is the Japanese/European ending theme, Cosmic Eternity - Believe in Yourself, written by Casey Rankin and performed by Keiko Utoku (who also voiced Sonic in the game) and Casey for backing vocals.

Some people might find the vocals cheesy but I really like them. Also Keiko has such an adorable voice (^^)

My second favourite track is Stardust Speedway - Good Future, again JPN/PAL. It reminds me of love and affection a lot.

The US soundtrack is rhythymless, unfocused noise by comparison to the beautiful art that is Japanese and PAL music.

Stardust Speedway, Bad Future is amazing.

I said that about the US track after discussing with a user here (remix10tailed) about it on another site. It's better than some, but doesn't fit CD, in fact Stardust Speedway's good future in USA should have been Bad Future and vice versa. The US tracks don't have as much feel or emotion in them as JAP/PAL to me, either.

The past music was compressed to PCM and encoded because there was no space left I believe, CDs weren't 700MB in 1993. The others are uncompressed WAVs.