My wife is a pet collector. That is her end game in WoW. Sure she does some other things, but this is what she really loves. She is not a mount collector. Just a collector of pets. I think she is at around 155 or so.
She is at over 200 Tol'Vir solver without getting the Hand pet. She has grown to hate Archaeology, but still presses on. Once she gets it, I forsee her not doing it ever again (unless of course the add another pet in Pandaria).
We just got her the Perky Pug pet finally. I have it on a ton of toons (all from WotLK). It felt like such a grind this time.
Now she is starting the painful process of getting the Kirin Tor Familiar from the random book drops in Dalaran. That seems like it will be a major pain.
She also has her eyes on grinding Shyguard Rep to get the pet from that.
Oh the humanity.