All right Ernie! I knew I wasn't the only one to own a Master System!
So yeah, the Sega Master System was my first console, and my favorite game for it, that STILL is entertaining today, is Spellcaster. It's a side-scroller with magic, that also has a point-and-click element when you get to towns and such, and the storyline is amazing. It's the first big game (one with passwords that you couldn't finish in one sitting) that my dad and I beat...the password feature was rediculous though...capital and lowercase letters, numbers, AND symbols...and the password was something like 20 characters. But it was a big game, so there were probably that many different things to keep track of. Anyone with a SMS (or an emulator, since the save state is WAY easier than the passwords, lol) should definately give it a shot.