damn i want to experience these too...
sadly, even though my computer is little more capable, i have to put most settings on low to keep my recordings smooth
uldum - specifically ramakhen and its lake/aquarium, seriously...
nagrand
tanaris
winterspring
some parts of netherstorm
some parts of mulgore
cape of stranglethorn
I've always enjoyed:
Nagrand
Booty Bay
Gadgetzan
Thousand Needles (both the old and new versions)
The top of Ironforge (before the introduction of flying mounts)