Another thing you need to realize on these quotes is that for a busy photographer, a DW is taking up an entire weekend or more. Those travel days are days the photographer isn't shooting, editing, or meeting with clients. As a general rule, destination weddings are significantly less lucrative than local weddings when you factor in the hours.
This is not to say that traveling to exotic locations isn't fun and exciting! However, shooting a DW is real work and the trip is FAR from a vacation.
Back to the original poster's question:
The average couple in the US spends about $2k on photography for a LOCAL wedding. Prices range from free at the low end to upwards of $15k at the high end. I suppose you could spend more if you wanted Annie L. to come shoot for you
For most full-time professionals, an 8 hour domestic wedding represents somewhere in the ballpark of a 40 hour time commitment (or more in some cases) to the couple when factoring meetings, editing, and perhaps an engagement or bridal portrait session. Now add to that the photographer giving up at least two additional travel days where he/she cannot be very productive (and certainly can't book any other paying gigs), and of course travel expenses.
When you are factoring in what photography should cost, be aware that a full-time pro is typically facing anywhere from $500-$2000 per day as the cost of a day of shooting, when factoring in insurance, rent, depreciation on equipment, advertising, etc... You can get more information on this here: NPPA: Cost of Doing Business Calculator
Thus, when you see someone regularly offering prices significantly below that, it is entirely possible that they are probably cutting a corner or two somewhere. This may just mean they are trying to break into a given market, but you should factor that into your decisions.