For me, The Sega Mega Drive....or Master System, can't quiet recall which one....but it was awesome, used to get out games from the shop to play on it as well, like The Lion King, The Jungle Book among others....including Sonic the Hedgehog.
Although, before that, one of the old Macintosh computers, to which I had the original Prince of Persia game on it as well as The Incredible Machine.....best game ever for me.