[yossarian19]

I like the 4.8 just fine. It's more engine than my suspension can really handle (so far)
The truck weighs 4900 lbs with me in it. With a 4L60E and the factory (I think 3.90) rear end, I can spin the tires in first with no difficulty. Second pulls pretty hard. Third is strong, still accelerating pretty quick. Fourth will hold and slowly accelerate up any of the hills I've driven, probably 500-1,000 ft elevation.
You do pay for displacement. The 4.8's are cheap, the 5.3's a little more. A 6.0 is a big price jump. Around here you can find a 5.3 complete for 750, 800. A 6.0 will run 1,200 to 2,000. $500 isn't life changing but it's more cash than I can personally ignore.
Doing it again, I'd go 5.3. For another $200 or so you get more power across the board, and if you go gen 4 you get VVT as well. Why not?