Who doesn't love trains?
(for that matter, who doesn't love Twilight Princess and Excite Truck as launch titles?)
HD for quite some time has been a matter of when rather than if with Nintendo. Miyamoto himself said around NSMBWii's release that he wants to see Mario in HD. It's just a matter of when Nintendo is convinced that it's cheap and mainstream enough to not be punishing those who aren't yet on board.
EDITS: Incidentally, I'd be hard-pressed to say they were wrong. Microsoft and Sony were just a bit premature, which left them with some console production cost woes. Sony, especially (Microsoft swims in money thanks to Windows). Nintendo being a game-exclusive company, that's not a misstep that they could afford to make. The flipside, of course, is that in the long-run Nintendo is under the most pressure to release new hardware.
And hopefully Nintendo will be paying close attention to the 3DS network structure - what works and what still needs tweaking - when they're ironing out their new system. It's already trouncing Wii in terms of response time when managing friends, and I know they're getting ready to kick their previous shop system in the behind. But there's still the typical Nintendo lack of communication. What good does it do to see what game a friend is playing, if you still can't tell whether they're actually looking for an online match without starting up the game on your end? Some kind of messenger is needed there.
Also on DeviantArt, Rumble, DLive.tv, and the Fediverse (@freespeechextremist.com and @bae.st)