Thunder Bluff, but only if you park a bank alt there, don't bother running over with your main. The bank & the AH is super close, and it's infinitely less laggy than Orgrimmar, especially around world events like Brewfest where you have some yokel running through every 30 seconds advertising beer. :)
Grab a lvl 1 Tauren and run him into Thunder Bluff, and bobs your uncle. Now, not only do you not need to go to TB, you can empty your bags from any city, saving you runs to Dalaran as well. If you feel particularly amusing, dress him up in something nice. Mine, for example, has a pair of snazzy tinted glasses and a diamond tipped cane. :)
That said, if you're going from the portal... yeah, Orgrimmar is a bit better for the closeness of the portal. I still maintain that a well dressed bank alt is preferable, though.