Over a lunchtime cup of coffee I had a quick search for websites claiming to show how to design an AVR onto a PCB, along with power supplies for it. Oh dear, oh dear, oh dear. No wonder we see so many bad designs.
The sites seem to fall into a couple of different categories...
1) Those that simply copy another website, dodgy schematics and all.
2) Those that make huge assumptions, and gross simplifications (usually wrong), about real world electronics.
It's a pity because there are a few sites out there that get it right but they tend to be swamped by the bad ones.