What all consoles can be emulated on the original Xbox?

I know of NES, SNES, Sega...any others? I'm thinking of getting my old xbox modded.

all you need to know is here.
http://forums.xbox-scene.com/index.php?showtopic=386399

you cant go far wrong with a modded xbox,oh and make sure you get xbox media centre on there,to play and stream all your files.

edit/some of those emus have been updated since,but that is the most comprehensive list you will probably get on the net.