Mario and Pokemon.
Mario
I always played Mario, whether it was for the NES, SNES, N64. My favorite Mario games are Super Mario World (SNES), Super Mario All-Stars (SNES) (includes all of the old Mario games), Mario Tennis (N64), Sunshine, Super Mario Kart, Mario Kart 64, MKDS, New Super Mario World.
Pokemon
I started playing Pokemon right when the first games came out, Red and Blue. I got a Blue. After that I continued to play Pokemon. The Pokemon games that I have are Blue, Gold, Sapphire, Leaf Green, Emerald, Pinball (GBC), Puzzle League (N64), Snap, Stadium 1, Stadium 2, Hey You Pikachu (this game sucked >_<), and Pokemon Trading Card Game. I loved all of them (except Hey you pikachu
). Even up to this day I play Pokemon.