I've got to go with half-elves...
Humans got access to extra skills and a bonus feat, not significant, but is a change.
Elves & Dwarves went through some minor tooling.
Halflings lost weight and became more kender like (I hate that BTW)
Gnomes had a complete body make over (How can you have a gnome without a gigantic nose) but finally lost that ridiculous mad inventor label the picked up over from Dragonlance (I hated that too)
Half-orcs changed from the pig like to the ape like facial structure (I like the piggies) and somehow became super-human (I never understood this, humans are taller than orcs, but half orcs are taller than humans???)
But that's just the core races, lets not forget the other re-tools
Kobolds, the dog-like reptiles of the underground became related to '??DRAGONS??'
All the animal type monsters went on Todd Lockwood's anorexia diet plan (I'm sorry the displacer beast just looks stupid! Thank goodness for the new DDM.)
Githyanki evidently got into bondage and S&M
Gold Dragons grew wings
Medusea became reptilian
Carrion Crawlers had all of their tentacles move below their mouth instead of all around it.
Hippogriffs grew talons instead of hoofs
Manticores evidently mated with primates at some point.
Umber Hulks lost weight
Ogre Magi moved from the Far East into the Western hemisphere
Vampire Spawn started to dress like Marilyn Manson instead of vice versa
And that's just Monster Manual 1...
