Whatever Joel (and the Starbucks employees mentioned) might think, the "expediters" do actually speed things up. Asking people what they want BEFORE they get to the head of the line means that by the time they arrive they've figured out what they want -- rather than weighing their options at the one point when they are in the critical path.
I haven't observed this in starbucks, but I've observed it in other places -- and I reason that starbucks is probably no different from other coffee shops.
"Personally, I was so offended by that expediter that I'm now getting my coffee at the Starbucks on 60th Street. The 58th Street branch can take a flying leap for all I care."
Hum... "Fuck you Starbucks, I'm so offended I'll go at ANOTHER of your branches! That will teach you."
I really like the system at Wawa: there are many touch screens. You enter your order and then take a printed receipt to the register, pay, get stamped, and get a copy. Then you trade your "PAID" stamped receipt for your sandwich when they call your number. Super fast and easy, never a line for the screens, and you can browse the rest of the store while you wait.