I love these games and I think the soundtracks are underrated as an essential part of their appeal. I'll Start with one:

https://www.youtube.com/watch?v=Kk72RMv9d0s

Tube of Medusa from Ecco2: Tides of Time.

Personally, I think the Sega CD version soundtrack is... fine, but it has a different composer. If I remember correctly, it;s the composer from the first Ecco. In my opinion, it's inoffensive, but completely forgettable.

EDIT: I have edited the topic to include older stuff.