So many good times with the Genesis.
Sonic series was amazing, especially those semi 3D bonus levels. Didn't like sonic 1 much though.
You all seem to forget about MICKEY MANIA. This game was amazing, the graphics absolutely superb, I don't think there is a better looking game on the megadrive. It had incredible variety. The first level was in black and white as it started in Mickeys Past and slowly became color. It just took the player through all the Mickey movies up to the present day. Really awsome.
http://en.wikipedia.org/wiki/Mickey_Mania
Shining Force series, first RPG I ever played was Shining Force 2, it was amazing.
Phantasy Star IV. I think I finished this game at least 5 times. I still wonder why they didn't make a remake. PSO just doesn't cut it.
Streets Of Rage 3, oh yeay baby. The kid with the Skates was awsome and later you got Roo to kangaroo hehehe.
How about Mortal Kombat 2 for the 32x. Or Ultimate Kombat 3. What about the street fighters.
I also really liked the game Syndicate. First time I played it it was on the Atari Jaguar, but the megadrive versionw as pretty cool too.
Beyond Oasis rocked my boat. Wonder what happened to that franchise. The animation and scope of the game where outstanding at the time.
Landstalker anyone? Shadowrun, the most awsomest cyberpunk RPG of the time?
And last but not least, Samurai Showdown which was as close as the Genesis ever got to the real arcade goodness.
Honorable mentions go to: Lion King, Aladin and Jursaic Park.