To me, answering a question as simple as "What is your favourite music?" shouldn't be difficult, but it is. The Sonic franchise, whilst I can't say all of its tracks have resonated with me, it nonetheless has a vast library that I could listen to for hours. I guess I'm in the minority when I say I prefer the US soundtrack of Sonic CD over the JP/EU soundtrack. That isn't to say I don't like the JP soundtrack (I prefer Quartz Quadrant from that soundtrack personally); it's just that I've heard it used so much it hasn't aged very well for me. My favourites from the US soundtrack include Tidal Tempest Bad Future, Wacky Workbench Good Future and all of Stardust Speedway. I also rather like some of the music from the 8-bit Sonic games on the Game Gear/Master System. My first experiences with the 8-bit library (and the classic games in general) can be contributed to Sonic Gems Collection. Underground Zone from Sonic the Hedgehog 2 has stuck with me, not just because it's a good track but also because I couldn't get past the anteater boss as a kid. The music of Sonic Chaos and Sonic Triple Trouble also deserve a mention as well. I think this part of the Sonic music library is underrepresented and should come back in one form or another. Finally as far as the "Modern Era" games are concerned, I like the Mission Street and Pyramid Cave from Sonic Adventure 2, Frog Forest from Sonic Heroes and Sonic Rush's soundtrack for how unique it is compared to the rest of the franchise.