I am a big fan of Nintendo
I currently have a Wii and a DSi, and I still have some older consoles too.
The 3DS doesn't appeal though, I'm afraid. It does nothing that makes my DSi look obsolete to me.
3d is no good to me, I'm blind in one eye anyway.
The lineup of games announced so far isn't exactly exciting.
I am interested in playing some of the old gameboy games again, but I suspect I'd be much better off buying an old Gameboy Colour or Advance and hunting down the games I want to play, if I could be bothered.
Maybe when the DSi actually breaks... but it looks pretty healthy at the moment, so I expect we'll be on atleast the third revision of the 3DS by then, if not onto the next handheld.