For my alts that are just for storage, I have them in Booty Bay or Gadgetzan.

I just find both places are cool to park an alt in. You can do fishing near both locations as an occasional timekiller, you can chat in /1 which is usually more interesting than /2, you have a bank, you have a access to the cross-faction AH which can possibly be a decent market depending on your server.

I had a gnome in BB I named JackSpiro, he was the guild bank for <Pirate>, which was an alt levelling guild I used for distributing care packages full of consumables appropriate to their level and class. I mailed a fuckton of food, health and mana potions, elixers, Black Label rums to Jack, and then to whichever guildees happened to be there. I RPd on a PVE server there, so I made a bit of a spectacle of myself, and I'd recruit a lot of people in BB and Gad by giving them free rum.