I think we can break the power forward position down to 3 areas:

You have the stretch 4....player with 3 point range. Ryan Anderson/Channing Frye
You have a Face-up 4...player with ability to face up and hit 18-20 footers and drive the ball. Chris Bosh/PAul Milsap
you have Traditonal 4...plaer with mostly post-up game and high post jumper (15 feet). Pau Gasol, Elton Brand (pre Phily)

I think we get a many players that have a combination of 2 of the 3, so it is not easy to peg them as a traditional or stretch.