That'll depend on what you like for games. I have a 3DSXL (blue Smash) that I have been planning to sell because I thought I'd never play it, but after not getting any firm interest in a couple of months, I'm thinking of picking up some games myself.
The main games I want are Fire Emblem: Awakening and Kingdom Hearts: Dream Drop Distance. Mario Golf: World Tour is probably the #3 game, and I might snag some Pokémon Game, eventually. Mario Tennis is on the fringe for me, and there are some Mario platformers to check out, too. Oh, and if you got the Majora's Mask N3DSXL, I imagine you'd have interest in the Majora's Mask and Ocarina of Time remakes, along with A Link Between Worlds. Original DS games also work on the 3DS, of course, and there are a couple of Zelda titles on it you could try (Phantom Hourglass and Spirit Tracks).
Best buy has B2G1 free on used games this week, in case you didn't know. Their stock isn't great for the popular, lesser-known titles (like Awakening, Pokémon, and Zelda), but you might take a look at what they have used.