Only minor things have failed mechanically.
Radiator failed around 100k and was replaced by a 4 core that has yet to fail.
Interior panels started to shake around 180k, but were easily fixed with new fastners.
Thermostat failed and overheated engine about 215k.
Love this truck, Chevy really did something right with this generation of trucks, and I am normally a Ford man, but would buy another one of these any day.
There was normal wear and tear on parts like the belts, tires, spark plugs and wires. But this is not a big deal because the 5.7 is so well laid out that it is very easy to work on, it has to be the easiest vehicle that I have ever preformed a tune up on.
I would recommend to run Castrol 20W-50 synthetic oil, it's thick, but keeps the car going.
The only reason I am not currently driving the truck is because of gas prices, I still own it because I just couldn't part with it. Damn fine truck, and it will get you from A to B more times than you can count.
Castrol 20W-50 is definitely the way to go, I have been running that in mine since I bought it in 95 and it is still chugging along great at 225000 miles, and it actually still gets about 12-15 mpg with a light foot.