Well, right now I'm trying to beat Phantom Hourglass and Spirit Tracks. I just beat Twilight Princess a few days ago. I'm pretty much two games away from having beaten every canon Zelda game. After that, I might start playing obscure stuff like the Game & Watch Zelda, BS Zelda, and/or the CD-i Zelda.
Phantom Hourglass gives me a lot of grief in the Temple of the Ocean King, though. A time limit, forced restart on failure, puzzles, enemies, AND avoiding guards is a painful challenge. Almost as hard as that Deku Scrub mini-game in Majora's Mask.