Well, since the old sticky topic hasn't been updated for 2 years now, I decided to make a new one. I will only list the latest versions of the best emulators for each console, with a link to their FileTrip download page (or, if there is no FileTrip download, I will for now post a link to the author's site, in time I will change all links to FileTrip though). I won't post direct links, because sometimes there's useful info on the page itself too. If you notice I forgot about an emulator, feel...
List of emulators for use on the NDS (UPDATED 2010)
List of emulators for use on the NDS (UPDATED 2010)