mine has to be sonic 06 i know its bad but i grew up playing it on ps3 (evan though i never got past the first level)

Generations because of the peak base game on top of the insane mods plus it was my first sonic game so I have insane nostalgia for it!

Unleashed (360/PS3) for his amazing day stages and very fun gameplay of its night stages. Also, the graphics and visuals are incredible for its time, the music is one of the best from the series, and it was really the last Sonic game that had a good budget to begin with.

sonic unleashed because of the 2 peak gameplay types + the music and sonic has the best design chara design W O O H !

Sonic Generations because he combine the boost formula with 2d formula and the OST and the level designs are so good

sonic 3 & knuckles, it's probably the first video game i've ever played

Sonic Adventure 1 because of the world hubs, the levels, the OST, the vibe, the different characters with their own gameplay and story and of course: Gamma's story!

It's gotta be Generations. Extremely solid level design, Excellent soundtrack in general, and established my respect for both Sonics ever since I was young... Great entryway!!

I love Mania's gameplay and art style!

2D, Its a tie between 3K or Mania. peak high speed platforming with split second decision making and I love the Blue Spheres game. For 3D its SA2 Battle, Every (Sonic and Shadow) level is a blast and fun to replay and the rest can be easily completed if you dont care about ranks