i just bought an '01 5.0L EB myself and i am very pleased with it. mine's RWD, as i don't need the AWD and i prefer the simplicity and weight savings of the RWD model. it had 179k on it and had recently gotten a new radiator, water pump, thermostat, serp belt and hoses, alternator, new upstream O2 sensors, new shocks and rear brake pads.
during the test drive i noticed a binding noise when the steering wheel was turned. after purchasing it i discovered it needed upper and lower ball joints, as the boots were gone and front sway bar end links. while replacing the ball joints i checked the spark plugs, which needed to be replaced, and also installed new ceramic front brake pads, as they were pretty worn. last week i noticed the 5th shock was leaking (and it made noise). i just replaced the 5th shock yesterday. still on my to-do list are tranny and rear diff service. oh, i also replaced the leather driver's seat bottom and installed a K&N air filter.
my truck is super clean inside and out and has never been subjected to road salt. all in all the 5.0L is a very reliable engine and the transmission's strong too. i'm hoping to get many more miles out of mine.
as far as checking your serp belt, you can look for cracks or missing rib rubber, but with modern serp belt material you're really looking at the depth between the ribs. some auto parts stores have a plastic gauge thing (free) to measure depth.
i am not aware of any particular problems with the '01 V8 models, just normal maintenance and wear items. good luck with your's!