Sonic Adventure. The combination of plot, character development, and action makes up for the minor flaws that do exist in the game.

Shortly after that I think would be Sonic (and Knuckles) 3.

The Sonic game I spent the most time ever playing was good old Sonic 2 on the Game Gear.

Other than that, I had fun with Sonic Adventure, despite it's little foibles here and there.

Why is this in MFC? There's a million of these topics in South Island, where topics of this nature should go...

Mine would have to be sonic adventure 2 battle, most fun 4 me in a sonic game

Sonic Adventure is so pro.
Yet, Sonic 3/S&K is so classic.

Sonic 1 GG

This was on the first page.

Good idea is to check that we have a topic first before you make it. A few times is okay, we're only human, but don't make it a recurring habit.