Here are my current major achievement milestones. While I plan on working on other things (top priority is world events, then dailies, then weekly stuff then this) I'd like to be done by the following dates:
Loremaster - Goal: get this within 60 days. i.e. by 15th Feburary
Battlemaster - Goal: get this within 45 days. i.e. by 1 April
Arena Achievements - Goal: Get 3v3 to 2200 achievement this coming season, finish by the next season.
Endgame 25-man Raid achievements - I expect this to be the hardest since it involves a lot of other players and tough encounters.
Things I'll work on casually:
Fishing (I need about 10,000 casts to get everything by some estimations...)
Most 10-man content
Reputations (26 weeks of Molten Core!)
And, of course, the world events.