Primary game:
Animal Crossing: Wild World - Yeah, it's eating away my life right now. I never played the GC version, but this game owns and I have to imagine that it probably wouldn't if it had to be played on a TV.
Secondary games:
Super Smash Bros. Melee - I have yet to stop playing this game for more than three months since I bought it. Usually not even one and a half months. Only the Pokemon series sees more playtime from me than SSB.
Final Fantasy IV - I'm at the end, but I'm holding off until I know whether the random stat decreases from level 70+ are back. I'm practically OCD about that stuff in my RPGs and tend to wish that all levels were fixed stat gains.
Dance Dance Revolution: Mario Mix - DDR's kind of an always-playable game like SSBM. Obviously DDR experts wouldn't be too challenged, but I'm not one of them.
Pokemon XD - I'm resetting until I get a Bold/Calm Lugia, then I want that post-game Lucky Egg so I can have two for my GBA games.
Backlog of games I need to get back to:
Pokemon Fire Red/Leaf Green/Emerald - It's a neverending pursuit, really, since it's my favorite game series. Like I said, I'm kind of OCD about stats in RPGs, so right now I have something like 50 Misdreavus, 20 Vulpix, 30 Dunsparce, 25 Smeargle, 60 Ditto, 15 Skarmory, 140 Magikarp, and some others to run through an IV calculator and then release if they suck. The vast majority of them have 2-3 perfect stats due to a lot of breeding beforehand, so I'm selecting the best of the best here.
Mario Tennis Power Tour - Haven't levelled up to 99 yet on either of my two files, and I need to start my third file. Other than Pokemon and Tactics Ogre, this is probably the only GBA game I own that I can see myself eventually putting 60+ hours into. FFVI and Tales of Phantasia will join the list in 2006, though.
Fire Emblem: Path of Radiance - I'm at chapter 21 and this is a great game. It's just that so much stuff has been released for the GBA/DS since FE9's release date that I haven't had time to finish it. Thankfully, there's nothing I want coming in January and only Drill Dozer comes before Super Princess Peach in late February, so I should be able to finally finish FFIV, Pokemon XD, Mario Tennis, this game, and the next game...
Mario Kart DS - See FE9, but replace "chapter 21" with "the mirror cups."
Metroid Prime Pinball - Awesome as far as pinball games go. I only picked it up because I was able to find it for $30, but it was worth it. I still have a couple tables to unlock (I've seen them, but not unlocked them), but Animal Crossing just dominates my DS time.
Dr. Mario and Puzzle League - Eh, the small sprites on Dr. Mario were kind of a turnoff, but I'd at least like to put a bit more time into Puzzle League to see what all the hype is about. I might just be spoiled by Meteos, and I'm not sure how well this bodes for Pokemon Trozei in March.
Battalion Wars - I'm still trying to like it only because I know I'm not going to get much of my money back anyway if I get rid of it. But bah, I just don't get the appeal. The controls are wonky and the camera is far too imperfect for my tastes. Among other problems.
Backlog of games I haven't even started:
Super Mario Advance 4: Super Mario Bros. 3 - Found it for $25, apparently a reissued version since it has the Nintendo DS logo on the back of the box instead of the e-Reader, and figured "eh, okay." I want to see what everybody's talking about with the toned-down difficulty on the GBA Mario games.
Ice Climber - It was $5 at Circuit City, so I figured it would have to be incredibly terrible to not be worth it. Unlike most of the other Classic NES Series, I've never played this or anything like it, so thought I'd give it a try.