Just for the full screen feature alone, the QT Pro upgrade is totally worth the $30.
You pay the "Apple tax" to get OSX, and then on top of it you pay $30 to get something as lame as "full screen"?!
Does the few lines of code it takes to resize the video cost so much to write? To add insult to injury Windows Media Player just does it... for FREE! As with every other freely available media player on the planet!
Let's just be honest with ourselves, Apple is not charging for the "Pro" features because they are genuinely good, they are charging for every tiny bit of functionality because they can.
Quicktime Pro is definitely not worth it, biggest rip off I've ever seen in my life. 1/2 the price of iLife, 1/4 the price of Leopard, and for what it offers it is waaaaaay overpriced.
I'd pay $3, that's all.