If there's one place that still illustrates where 2D games can shine it's the shmup genre. Not that this genre gets much attention, but I don't think anyone will kill it off for awhile. I'm glad to see Shikigami no Shiro III (Castle Shikigami III) is going to be released on the Wii and 360 (I believe the 360 version is a Live Arcade title), and I really hope ESP Galuda II gets a port, as well. The nice thing about having this sort of thing on newer systems is that the big problems with ports to older systems (flicker and slowdown) are less of a problem on a more powerful console.
The thing I've always loved about 2D games is that the camera isn't usually an issue. Frankly, this is why I generally don't like 3D platformers: manipulating the camera is usually a chore, and the price of fudging it up in the slightest is usually a fairly long fall. This is why I like 2D Mario games and erect holy wards to keep the 3D ones away from me. I like focusing on actually playing the game, and I find camera work to be a major detractor. I'd love to see some high-profile 2D platformers on newer consoles. The big advantage is that the relative simplicity of such a game would give the developer plenty of time and system resources to introduce a compelling set of gameplay mechanics. Sales could be disappointing, I suppose, but I have faith that if it were a good game, and the lot of us lied our faces off about it being the best game ever before it came out, enough people would buy it to make it financially worthwhile.