Very well...
Gargoyle, Archer: From Dragon #223. There is something endearing about a malicious stone cherub that shoots arrows at people when nobody is looking.
Golem, Nyraala: From Dragon #255, the nyraala golem is an illithid creation of flesh and psionically active mucous. I've been hoping to see it in 3E at some point, since you can never have too many tentacle monsters.
Oard: From CM6: Where Chaos Reigns. The oards are humanoids who are grown in vats and use very advanced technology. They're resistant to magic and mind-affecting effects and a good source for really weird loot that the PCs can kill themselves experimenting with.
Rohch: From Monstrous Compendium Appendix 11: Forgotten Realms. The rohch is an unspeakable (or at least unpronounceable) crossbreed between a beetle and a wolf. Creepy things.
Tunnelmouth Dweller: From Dragon #267. I think this one has some of that old school, Gygaxian spirit in that it's a monster that doesn't really make sense anywhere outside of a dungeon. Basically, it's got a huge mouth, which it keeps open, blocking the entire dungeon. Then it waits for something to walk in.