And Las Vegas, the Mecca of tips.

I am of two minds on tipping concierges. Yes, it's their job -- but it's also the bellman's job to carry your luggage to your room and the valet parking guy's job to retrieve the car -- but I (and most people, I think) always tip these service providers.

My general rule is to tip blue-collar employees for personal services. Concierges see themselves as professionals, so I am not sure that a tip really makes sense. But I agree that tipping should be only for above-and-beyond fulfillments.