If it has a pair of eyes and a butt-hole... it's a keeper!!!
Seriously though, I follow the regs for wherever I'm fishing... and even then I'm pretty picky about what I keep. If I'm just going to get a couple tablespoons full of meat off of each fillet, it isn't worth my time to keep that fish. On the other hand, if I catch a magnificent specimen that has lived a long time I'll just take a pic and put it back where it came from to live another day. I also will rarely keep more than 12 fish per outing, a dozen fish is about all I want to clean at one time.
Since the advent of modern digital photography it's much easier to just take a pic and let the fish slip back into the water. You still have bragging rights and the fish gets to live another day... it's a win-win combination.
