Mischief Makers on the N64: Maybe not the best Treasure game, but it's got a fun aesthetic, the grabbing and shaking-based gameplay was enough of a twist on the normal platformer formula to keep it interesting, there was decent stage variety, and it didn't overstay its welcome. Also, I'm still not entirely sure what an 'Ultimate Intergalactic Cybot G' is.
Henry Hatsworth on the DS: An action platformer on the top screen and a Bejeweled-esque puzzle game on the bottom screen, with lots of interaction between the two. The game also has memorable visuals and music, some pretty funny moments, and provides a pretty decent challenge on top of that. Plus, you get a super mode where you control a tea-powered robot suit.
Folklore on the PS3: It can get a bit repetitive, but there's a lot to like about a real time Pokemon-esque murder mystery instpired by Celtic folklore.
Majin and the Forsaken Kingdom on the PS3: The boss fights could have used some work (especially the one in the desert with all the ships), but there weren't that many of them and the action/puzzle sections in between were a blast. I loved the visual design, and I thought mechanics of commanding and working with a big AI partner were very well integrated into pretty much every aspect of the game.
Ogre Battle 64: Person of Lordly Caliber: More people probably know about this one, but I don't here it talked about much (even compared to other games in its series) and I'd like to see more games attempt its mix of real time and turn-based strategy gameplay. It made me feel more like the commander of an army, and less like an omnipresent force inhabiting the bodies of 8-15 assorted dudes.