Obviously this topic is about the home cities (including gilneas/bilgewater).
Here's a quick list of things you can farm. The Heroics finally give reputation so can be used to farm. (Note: yes, ofcourse just doing the random dungeons works too but these ways can be faster).
To avoid the 5 instances/hour limit, type /console startproject while you jump in.
-BRD. I'm not even going to bother to explain it further since it has been reposted a LOT.
-Azjol-Nerub: Get a party for this, and farm the first boss. Dont bother doing each Watcher seperate, the gear is good enough to just pull all and kill watchers->boss (or skip watchers if you need achievement) The boss will give the full 300 rep and the adds 30.
-Trial of the Champion. This one is quite obvious: there's barely trash, and the trash of 2nd boss can be all pulled at once for max effiency.
-Halls of Lightening. Run in, pull boss (he should be very close to entrance), kill him + adds (bonus rep) and run out. Rinse and repeat.
-Ramparts. This is only for mages/rogues/hunters/any other class or profession that can reset a battle. Go to the last boss, kill drake, reset, rinse and repeat.
-Aldun