Breaking the Sound Barrier The achievement for learning 310 percent flight. I would assume this is an automatic deal if you've already got a super-fast flyer to call your own, but otherwise? Plan on dropping 5,000 gold for this.
Did Somebody Order a Knuckle Sandwich? This will almost certainly become a Feat of Strength, as weapon skill has been removed from the game.
Dual Talent Specialization On the beta right now, the dual talents feature is still available as of level 40, but now it'll run you 100 gold rather than 1,000. I'm always pleased to knock another expensive achievement off our list.
Going Down? I've included this here, as I've run across a quest in The Barrens while leveling my troll druid that will automatically get this for you (it involves some backfiring goblin technology, as you'd expect). I'm not sure yet whether there's an Alliance equivalent.
Master of Arms As with Did Somebody Order a Knuckle Sandwich?, above, this is likely to become a Feat of Strength. For the moment, it still appears as an ordinary achievement.
Mountain o' Mounts (Alliance) and Mountain o' Mounts (Horde) The current achievements are unchanged but will become easier with new reputation and dropped mounts in Cataclysm. As with the small pets achievement (below), we'll probably see an updated version eventually, and we know that camel, fossilized raptor and stone drake mounts are being added.
Shop Smart, Shop Pet ... Smart As above. We've seen reports of seagull and armadillo pets so far. One question for anyone who's spent a lot of time in Stormwind on the beta -- is Lil Timmy still around? I have yet to see him on my Alliance druid.
Twenty-Five Tabards An upgraded version may or may not occur. Based on a Wowhead report on updated icons for dozens of abilities and items, we should see new tabards for the Earthen Ring, Baradin Wardens, Hellscream's Reach, Dragonmaw Clan, Explorers' Guild, Guardians of Hyjal, Therazane, Tol'vir and Wildhammer at the very least. However, that doesn't necessarily mean that all of these tabards will be available to players; some may only be seen on NPCs. Worgen and goblin faction tabards should pop up somewhere too, but the developers have confirmed that they don't plan to add them to the Argent Tournament. Stay tuned.
As a general rule, the "introduction" to new zones for 80-85 characters is fabulous, and Blizzard really pulled out all the stops to get you invested in the leveling process with cutscenes, special events and a great story. Questing from 80 to 85 is an absolute pleasure, and I could not praise the work they've done here more. So far the least elaborate introduction is Mount Hyjal -- you really only get a glimpse of Deathwing on your way in -- but I'd be hard-pressed to pick a favorite from among Deepholm, Vashj'ir, Uldum or the Twilight Highlands.
Hemet Nesingway: The Collected Quests This is still in the game, which surprises me. Jeff "Tigole" Kaplan (former lead designer) has mentioned before that he thought The Green Hills of Stranglethorn was among the worst quests of classic WoW.
The First Rule of Ring of Blood is You Don't Talk About Ring of Blood We've mentioned this previously, but it's an updated version of Of Blood and Anguish and points to a new arena-style quest in the Twilight Highlands. My main is now questing there but hasn't encountered it yet.
Round Three. Fight! The individual achievement for the Twilight Highlands arena quest, above.
The Loremaster (Alliance) and The Loremaster (Horde) The total numbers required for Loremaster are going to change, subject to quest additions and subtractions in old Azeroth.
New zone achievements Rather than the current continent-wide numbers, there will be a list by zone of the number of quests required. Blizzard is still tinkering with this, though.
Beware of the 'Unbeatable?' Pterodactyl I don't think this has been implemented yet; I did every available quest in Mount Hyjal and don't recall any jousting.
Breaking out of Tol Barad Tol Barad is going to be one of the new daily quest hubs in Cataclysm, but to access the quests, your faction will need to win it à la Wintergrasp. At least, that's how we think it works now; there are both Horde and Alliance encampments on the Tol Barad peninsula north of the actual battlefield, and it's possible that the winning side will simply have access to more quests rather than all of them. However, on the current beta build (12857), the winner seems to get them all, although specific quest availability seems to vary by time of day. However, the quest NPCs are bugged right now, and I'm reluctant to queue for Tol Barad before level 85, so my grasp of this isn't as firm as I'd like.
In a Thousand Years Even You Might be Worth Something I'm only a third of the way through Uldum questing so far (I think) and have no first-hand information on the Harrison Jones quest(s). Amazing zone, though.
Zone achievements As with the rest of "old" Azeroth, the Cataclysm zones all have a specific number of quest requirements for achievements. Requirements for the Alliance and Horde don't differ anywhere other than Vashj'ir, where Alliance apparently has 10 more quests than the Horde does.
Loremaster of Cataclysm (Alliance) and Loremaster of Cataclysm (Horde) Par for the course given the continent questing achievements elsewhere, but this is going to be the most enjoyable part of Loremaster by far. I loved Wrath questing, but Cataclysm blows Wrath out of the water.