My personal favorite console...
Well, I'm leaning toward the Nintendo GameCube, as it was either my first or second console (vs. PS1), so many of my favorite games are on or from GameCube, (Zelda: Collector's Edition was the first game I ever played) but the Dreamcast also has so many good games I enjoy as well, like Jet Set Radio and Sonic Adventure, and introduced many gamers to online gaming, and I'll even say I like that clunky speedboat of a controller. And the VMU- that was a very cool idea. Kinda like today's WiiU GamePad. So for me, it's a tie between the GameCube and Dreamcast.
The MegaDrive also is a personal favorite, but I'm not as familiar with it or many of it's games. (I only really played MegaMan: The Wily Wars, Monster World IV, Popful Mail on the Mega-CD Addon, and Sonic's many gems.) (See what I did there? Gems? Sonic Gems Collection on GameCube? Okay, I'm done.)