I am not a technical expert, but I have done a bit of digging to find out just how much we can expect to gain with 64-bit processing. The answer is none, depends and a lot.
For day to day stuff, you can expect virtually no benefit. Word, emailing, browsing, etc. Not that those apps really need much speed boosting.
Photoshop may benefit a little, but not a as much as you would think.
The biggest benefactor on the list was...games. Yes, games. Followed by high end video and 3D and database apps. All would have to be compiled to take advantage, of course, but my understanding is that Unreal(?) or Doom(?) is being recompiled for 64-bit processing in the future.
Call me a cynic, but I am also not expecting big boosts from Panther as far utilizing 64-bit operations to impact the overall performance of the machine across the board. Marginal, yes. Big, no.
I predict a slow trickle of optimizations over the next two years, at which point we, as a group, can say with a straight face that 64-bit is the bomb. It will not be that way for a while.
It would be in Apple's best interest to optimize FCP for the G5 and 64-bit. That's their flagship app and it needs to really shine. I'm quite sure they're working round the clock to do so.
Did anyone see this?:
http://maccentral.macworld.com/news/2003/09/12/finaltouch/index.php?redirect=1063464320000
"FinalTouch software lets users process infinite color effects in real-time at a resolution of 2K (2048 x 1556) on a G5. The software provides more than 30 color nodes to be applied simultaneously to original film scans to create real-time color corrections, effects and grades." Holy crap, that's some serious performance!