Game Gear
Shinobi 1 & 2- Any time I get a chance to pimp this game and its sequel I take it. Unique to the Game Gear and can hold their own against most (all?) Shinobi games.
Solitaire Poker-Yes it's true! This was a random gift one Christmas and I played the hell out of it. Pretty much what it says: a combination of solitaire and poker. Still need to find a copy for my current collection......
3DS (Excuse the noobishness)
Project X Zone-Not the best game technically but I love it anyways for all the nostalgic trappings
Fire Emblem: Awakening-Great depth and I love strategy games
DS (Noobie here as well)
Hotel Dusk-I'm waiting for this game to shoot up the price charts. Seems like everyone likes it. Maybe it's just in large supply.
GBA
Advance Wars-I lapped it up like a starving cat