Thanks for the suggestions guys, I hadn't though of Kargath (my warlocks are Horde) even though I've had to drag all my characters there at some point, Stonard is a good idea too - although I could just sit right outside the dark portal.

Do you think Light's Hope Chapel would be useful as well? You need to get the FP there to connect the Undercity and Silvermoon flight paths.

I was thinking that Shattrath would be good because people want to GET there before lvl 60-62.