This post was from a user who has deleted their account.
World Explorer is my favorite achievement i have gotten thus far. I remember when achievements first came out i ran around everywhere in Eastern kingdoms and Kalimdor on my ground mount trying to find each section to uncover the the achievement., then flying all around outland. Was so disappointed that i couldn't get all of Northrend without being able to fly. I tried running everywhere i could trying to get the achievement only to die multiple times to enemies higher lvl then I.Once i was able to fly the first thing i did was fly all over Northrend to unlock all the areas i couldn't reach from the ground and finally got my achievement. Was a good day.
To be honest, my most favorite achievement would be the "3000 Quests Completed" achievement. I love the lore of World of Warcraft, what can I say? You will often find me debating origins of characters or talking about the good ol' days before the Cataclysm with my friends. I also love the title that you get for it. Actually, two titles: the Seeker and the Loremaster (assuming you did the quests before it got easy to do in Cataclysm). I proudly wear my "Seeker" title all the time, everywhere. To me, this achievement almost embodies(figuratively) my love for for the games story and the good times spent with it.
Into The Wild Blue Yonder - Helped make my slow ass go faster!
I would say my happiest achievement was my Thunderfury but that was before achievements were actually in game.So for the achievement I actually worked towards, I'd have to say glory of the icecrown raider (25 player).
The achievement I am most proud of is Grand Marshal. I have never been interested in PvP until they introduced Rated Battlegrounds, but now I really love to play RBGs or even just random BGs :) I'm thankful for having a team that is fun to play with and doesn't rage even when things go wrong.
I'm really proud to have been killed by Deathwing, and get the Stood in the Fire achievement.. That was the most beautiful death I had. Ever. :-P
Well, though I really I tend to not care much at all about achievements myself, be they mine or others, I suppose if I had to pick one it would likely be It Belongs in a Museum! , mainly because for personal reasons I love the Professor title, and mainly because for me, that 20th rare relic happened to be Zin'rokh, Destroyer of Worlds, aka Zin'rokh Destroyer of Lives, and I will admit after the insane amount of time spent grinding for that sword, I did seriously doubt my sanity continuing on, but alas those horrible, weeks of the Happy Super Funtime known as Archaelogy grinding finally came to an end, and just so happened to gain an awesome title on accident...(which is by coincidence how I gained pretty much 99.99% of all my acheivements)
Oh I'd have to say that Hydraxian Waterlords would be one of the achievements I'm most proud of. I was never crazy enough to go for Insane in the Membrane and while I do have the raiding achievements for LK I feel like those were more guild focused than personally done. I did raid MC weekly from the time it came out until BWL was released but even then I was only up to a few thousand in Revered. After that it took about 15 weeks of soloing the place during Wrath to get the achievement. It wasn't hard, just time consuming and I'm more proud that I had the resolve to keep going back when it seemed it was going to take forever. Otherwise, I'd have to say probably Charger as I was like the 3rd person on my server at the time to get the paladin quest mount.
Has to be for me, nothing felt more satisfying then finally being done with it after so long. Interactively learning the history of azeroth took some time and patience, but after-all was definitely worth it.
Not sure if this exactly counts, but my favorite is Hand of A'dal. My guild and I worked so hard to down Kael the Guildbreaker (a good 5-weeks total), a feat that came about in one random night we put together for the heck of it. I don't think I've come across a kill yet that has eclipsed that experience.
Original Amani War Bear!