2011 was the year I got into the Sonic games, and while of course Sonic Adventure was my favorite from the beginning, and Sonic the Hedgehog 2 (first game I beat) and Shadow the Hedgehog aren't far behind. Colors was pretty fun aside from a few parts, I thought Generations was pretty good, and Lost World and Forces were awesome. I know many hate them but they're really high up my list.
And I never got the hate for the Deadly Six as villains. Maybe Zavok is a bit generic (not that that's a huge issue if he feels compelling and has a cool design and is a threat), but the other five, aside from their designs, have their own unique personalities. (Which is more than can be said for the Koopalings in the non-RPG Mario games as those have far less story than Lost World or Forces (yet they're more popular).
Zazz is the hotheaded aggressive one, and a bit crazy
Zomom is the gluttonous one who loves sandwiches
Master Zik is the wise, elderly one who loves gardening
Zeena is the extremely vain one
Zor is the Emo one. I always found him fun to have around, even if some of the stuff he says is pretty depressing.
And while their appearance seems more expected for a Mario game than a Sonic game, they're quite dark as they want to kill everyone on Earth. Personally, I couldn't get enough of watching their cutscenes and battles, and once there was a second Wii U game, I got the Wii U to play both it and Lost World.