These mounts are fantastic. I love them all. Panther, turtle, crane, yak, water walker. All of the super cool, and I want each and every one of them! For all my characters!
Have a look-see...
Despite the fact that I have the Mountain of Mounts achievement, I'm still avidly collecting mounts. And now, with MoP, this behavior will only more rabidly increase since the mounts are OMG cool!
In fact, it was all my mounts that prompted me to get into addons again. (That, and the fact that my new shiny has more RAM than the OS can address means I have plenty of room for addons now.) I installed the GoGo Mount addon, which I adore.
All it does is randomize which mount comes up when you issue a Mount command. Plus it knows whether you can only summon a non-flying mount, and you can pick favorite mount(s) for specific zones. Quite keen.
Using it has reminded me of mounts I've long since forgotten, and that's no way to be!
MoP + GoGo Mount = awesome.