I am a purist to a point. I like to see trucks that look like they did when they rolled off the line from 50 feet. As I get closer, the differences from stock are fun to look at and compare (and if it's a good idea, to appropriate).
I don't have a problem with repop sheetmetal, I don't have a problem with new paint in different colors than were available at date of manufacture, and I don't even care so much about someone doing a ring/pinion or a brake swap.
My truck is my TRUCK. If I need to haul a bunch of dirt, I'll use my truck. If I need to move a bed for someone, I'll use my truck. If I need to go pull someone else's truck out of the lake because they miscalculated when pulling their boat out, I'll use my truck. It will be used, and because of that, I'm not going to be wasting time making it show quality. I want to drive it and use it without being afraid to.
As Eric said, the small things don't matter so much, if you're not looking to build a trailer queen.