Hard to make a top 10 list without it being all just the main vocal tracks for their respective games (Open Your Heart, What I'm Made Of, etc) since all of them are tear-jerkers for me since I listened to them so much when little. Reach for the Stars from Sonic Colors specially consistently makes me sob like a Victorian mother at all the good memories it brings, so I'll exclude those types of tracks along with character themes from the list for the sake of variety. Also keeping it one track per game.
I have a really hard time picking favorites since really, I believe every song to have their respective "vibes", and thus can be enjoyed differently and, frankly, I'd make this more of a top [insert number of literally every Sonic track known to man here] list, so... do keep that in mind.
With that said, we have:
1) What U Need (Blazy Mix) - Sonic Rush
2) Soarin' Over the Space - Sonic Adventure 2
3) Westopolis - Shadow the Hedgehog
4) Sand Ruins - Sonic Riders
5) Bingo Highway - Sonic Heroes
6) Bad Taste Aquarium - Sonic Adventure
7) Vs. Character - Sonic '06
8) Tabloid Jargon - Sonic Mania
9) Death Egg Zone act 1 - Sonic 3 & Knuckles
10) Scrap Brain Zone - Sonic 1
Oh man, but there's also
this track I really like, and I left out
this game, but is that track really above that other one? GAAAAHHHH!!!
..Making a top 10 list is hard when you like them all...