Bob Cringely of PBS fame has it on good "rumor" authority that Apple's planning to add H.264 hardware support to all of its machines. As in the iMac, the MacBook, the MacBook Pro, the Mac Pro, and even the Mac Mini. Why is this important? Because a $50 hardware chip (that's how much it costs Apple) will be able to handle all iTunes video flawlessly, allowing the CPU(s) to relax and put its feet up, instead of busting its ass rendering Pirates of the Caribbean like it does now.
The benefit of this is the ability to play video smoother on lower-end hardware (see Apple TV), and the possibility of DVR usage. How's that? Because this same H.264 chip is capable of encoding as well as decoding, which means you may be able to turn any Mac into an H.264 DVR, or "effortlessly" record screencasts without taxing your CPU, which is doing whatever it is you're currently recording.