if you loved the SMS, the turbo grafx is basically the same thing with enhanced grafx. If you can find them, get:
Fantasy Zone
Outrun
Space Harrier
All 5 wonderboy games (though 2 require CD)
Original Turbo games:
Legendary axe 1 & 2
Nuetopia 1 & 2
(although not original) New Adventure Island
Blazing Lazers
Star Soldier
Get the jap converter, too. It let's you get some truely great games. once you get it, get
bomberman 94
Soldier Blade
Star Parodier (a great CD game)
Hope this helps. BTW, congrats on getting a truely great system. I love my PC Engine... and i'm sure you'll love your Turbo Grafx, too.
-Cooljerk