14 CFR 121 contains the legal limit for flight time for airline pilots in the US (you didn't specify whose regulations you were interested in):
(a) No certificate holder conducting domestic operations may schedule any flight crewmember and no flight crewmember may accept an assignment for flight time in scheduled air transportation or in other commercial flying if that crewmember's total flight time in all commercial flying will exceed—
(1) 1,000 hours in any calendar year;
(2) 100 hours in any calendar month;
(3) 30 hours in any 7 consecutive days;
That gives you a rough idea of what the airlines would like every pilot to fly in order to best utilize them. The actual number of hours flown however depends on a lot of things, including the lines that the pilots bid on and whether or not they pick up any extra trips.
While this appears less than a "typical" job, keep in mind, this limit only applies to flight time (which oddly enough includes time taxiing the airplane). The crew will spend additional time before the trip, between each leg, and at the end of the trip taking care of things like pre-flights and post-flights, getting clearances, doing paperwork, etc.
