If you're fairly new to guitar (as your username suggests), just head down to ultimate-guitar.com and pick out some simple songs by bands that you like. There are enough tabs there to last you a lifetime.

But if you're doing commissions, and if you want something tricky... ;)

See if you can get your chops around the tab for "City Nights" by Allan Holdsworth. I'm working on it at the moment, and it's not the easiest thing I've ever attempted.