The only Battle Network game you have is 4? Yikes. It's generally agreed upon that 4 is the worst in the series (Mainly for the story and all the mandatory mini quests). You should get 2, 3, and 6, as they are the best in the series. (Admittedly, people also hate the soul system of 4 [and by extension, 5] but I personally love it. I hate trying to obtain them all, but the system itself I love.)
I always enjoy recommending Summon Knight: Swordcraft Story (GBA). It a dungeon crawler, but the battles are on a 2D plane, kind of like Zelda 2, but more action oriented. You're also missing Drill Dozer, which is a lot of fun, and the entire Mega Man Zero series (Which you can get as the Mega Man Zero collection on the DS). Custom Robo (GCN) is an amusing game that is great 4 player brawler, though it's obvious when someone isn't familiar with the game on multiplayer. Henry Hatsworth and the Puzzling Adventure (DS) is a unique action/puzzle game with a lot of charm. Your SNES collection has most of mine in it, and of the few you don't have, the only one I think I could actually recommend is maybe Pitfall: the Mayan Adventure, or maybe Wario's Woods, if you're into that sort of thing. What I can't understand is, you have Sonic and the Secret Rings, but not Sonic Colors. That is a real tragedy. Blur (360) is phenomenal, as Split/Second. I'm more of a kart racing fan, but if I have to drive cars, it would be in these games. There's also Resonance of Fate, a good but hard 3D turn based RPG that no one knows about. And finally, there's Bulletstorm, a First-Person Shooter that laughs in the face of other FPS games because those other FPSs take themselves too seriously.
