I find that there is a difference between the types of clients I work for: the clubs are very particular about how much you are charging and all related expenses, the private and corporate clients generally aren't. If I have to travel for a gig, it's not going to be for a club so I name a price that is more than enough to justify the gig, the travel and quality accomodations.

A freind of mine once said "I charge too much and then back off a dime". So I ask for too much and then offer a "special rate" if the customer requests it. Often they don't.