|Start at the end, my friend.|
By far the easiest bit about the Mount achievement, and the key to understanding just how many you need to hit certain targets, is the mounts that aren't blue or purple. If I'd been collecting these things simply on the Hunter she'd still be stuck on 199, but fortunately for me my linked Battle Net account includes not simply a Warlock but a Paladin... That means they both provide two additional mounts to the total (but note, NOT four because your total only includes mounts that are rideable by the user.) Then there are the Engineering mounts: you can only make two 'default' mounts as an Engineer (my hunter isn't, alts are) but everyone can ride them. So, before you begin this entire endeavour, having a Paladin Engineer who's also a Tailor might be an advantage. Yeah, there's Flying Carpets there as well you can add, on top of the various 'extra' mounts Pallies seem to pick up just by being awesome. Nobody said this was going to be easy, after all.
I could write you a comprehensive guide of what you can get where, but Warcraft Mounts is probably the best place for you to go and see what you can get and where it comes from. That's pretty much the easy bit: buy all the ones you can for cash, see what you have left after that. Then there are the individual rep grinds, the 'chance to drop' mounts from Dailies (Oracles/Big Blue Laydees in Wrath) and after that you'll be forced to start making some serious choices... and then it's not about looking at the mounts you do own, but the ones you don't. The main Warcraft Database is as good as any place to start on that front: right now, I have 82 possibilities left to farm, should I choose to. Many of mine are Meta Achievement mounts, TCG Mounts, or the impossibly low drops from boss kills that would require me to do a Daily/Weekly Circuit of Disappointment (TM) Onyxia's in there, as is Malygos and the dragon from Skadi the Useless in Utgarde. There's no Magic Rooster or Mimiron's Head, or Time Lost Proto Drake. However, there's also no Archaeology mount or Anzu, both of which I could be trying for regularly if I put my mind to it.
|It's not a Bat. Or indeed a cat, in a hat.|
There are some tricky ones in there: I have a PvP Halaa mount, for instance. All the purchasables are in there too, but the Jewelcrafting fivesome are missing so there is room for flexibility. However, two of my last five mounts were grinds over several months for both: the key to this achievement I thing is patience, and the understanding that actually, once I hit 200 it's not like I've actually finished anyway. In fact, once I've done this post I'll be making a list of the next ten doable mounts (of which the JC ones will be included) and I'll be off to start including these in my Weekly Faffing Pattern. This achievement is pretty much the equivalent of painting the Forth Rail Bridge. It takes so long, once you get to the end, it's time to go back to the beginning and start all over again.
|It's a metaphor. Really, it is.|
Perhaps the most important thing of all if doing this Achievement, or indeed any other which involves a lot of doing stuff on your own, is to share it with people so you don't end up either getting disheartened or going insane. Friends can help this be a far less painful task than it might be... and the trick is to remember that sometimes, winning isn't the best bit. If you're grinding with someone, don't automatically expect them to give the mount to you on a roll. Let them roll with you, and if you lose, enjoy their moment as much as it were your own. Some of the best moments I've had in game during my time collecting were when I wasn't the winner. It's important to have a sense of perspective about this, after all, and it's why a lot of my 'guaranteed' mounts were the ones I derived the least pleasure from. Solo is great, but sharing actually is better.
After all, the journey's not simply about reaching your destination, it's what you learn along the way.
PS: If you'd like to see which 200 I got along the way, my Flickr photoset of them all can be found here.