That is awesome with the pets, I wanted to start collecting them, but I figured at this point, it is so far along in the game that it would be fruitless.
It's really not too bad, if you like collecting things

There are a few hard ones that you will probably skip... dragons are 1/1000 and there are four of them, so... I personally farm the gold and will buy them when they come up on the AH (like I did with the worse than 1/10000 drop rate of the Hyacinth! - 2000 gold, gah. But that's well over 25,000 kills to get a 90% confidence of drop... and 25,000 kills > 2000 gold!)
Err.... anyway, you can always go back to get the pets, I mean

I'm not collecting any more except as they come up (I wanted the 50, but there aren't even 100 pets in the game to get the next accomplishment)... but I am collecting all the cooking recipes. Need one from Rokk, a bunch from horde and dalaran and... the dirge's. Need to find a group for BWL, which will end up being the hardest, I think. But, I think I'll have them (except maybe any added dalaran ones) in about a month and a half, no thanks to Dalaran. (Give me rhino dog dailies, PLEASE!)
Inbetween I'll be farming for Pilton's bag, dalaran signet and the wooly mounts. 50,000 gold, here we go!
And then... sadly... I'll be farming ZG, AQ and Strat for mounts (and the 15,000 gold or so to buy the rest of them.)
Damn, that's a lot of things to do.