I see a lot of 6.0s. Saw one not too long ago with 284k that came into the shop; head gaskets are notorious on the 6.0 as well as having to take the cab off for the two rear injectors....
Ive replaced all my injectors one or two at a time cause the race tune I was running was starving them of fuel and the truck would start skipping, fuel pressure was dropping to 30psi under WOT and they dont recommend less than 45psi. You dont have to pull the cab, I have literally driven home from work at 6 pm, pulled the valve cover and replaced an injector or two on one bank and had it buttoned up by 9:30pm and ready to drive back to work the next morning. Ive actually replaced all the injectors once and a couple twice (13 injectors total) before I decided to just put an agressive tow tune in and drive, havent replaced an injector since. One day I may put a stronger lift pump in and run the race tune some more, but Im past my street race days now, LOL.
My EGR cooler was replaced at 52000 miles by ford since it was still covered, they put a stock one one it. The head gaskets and bolts are stock. I blew a turbo at 130,000 miles with the race tune at 42 psi boost the exhaust wheel started coming apart. I had a water pump pulley crack just recently about 200,000 miles on it and I replaced it with the updated part that the late 04 trucks got anyway, and I had to put a glow plug control module on the truck this spring since it quit powering the glow plugs. I've been through two clutches and a rear axle too from clutch dropping with 37 and 35" tires on the truck, I used to be really rough on this truck. The only problems I dont blame on my own stupidity is the water pump pulley, the glow plug module, and the EGR cooler, every thing else has been from serious driver abuse and a 160 hp tune.
The truck has only been down two weeks total since I bought it new in September 2003, one week at ford for the EGR cooler under warranty, and one week to find a new 10.5" axle since the carrier caps let the bearings spin and chew the housing up. Everything else has been done in a night after work or a Saturday afternoon here or there, I dont really feel like Ive been working on it constantly, no more than any other 10 year old 206,000 mile vehicle.
This months Four Wheeler magazine has a pretty good article about the 6.0 and lists its weaknesses over the years. Every vehicle is going to have its issues, my dads LBZ Duramax has eaten two $300 EGR valves (the electric motor part) and Ive had to pull it apart to clean the sticky mechanical EGR valve portion once, that took several hours to get it apart and cleaned. He's also had the front wheel bearings go out and the HVAC blower resistor and wiring harness burn up.