Check out a band called Clutch.

Their guitarist, Tim Sult uses his wah pedal near constantly and yet, if you're not listening for it or if you're not watching him live, you'd never know it most of the time.

Also, he writes really cool sounding riffs that are usually pretty simple to play (which I think is important if you want to focus on learning how to use your wah).

Check out: "Ship of Gold," "Basket of Eggs," "Release the Kraken," "The Soapmakers," and "Big Fat Pig."