Video editing, compositing, graphic design, etc.. that's all I do.
I was using a PC, and sure you can build a pc which could rival a dual G5, you'd spend a good bit, and possibly spend a little less overall, but at least in my opinion, you can't really beat the mac setup. You crash once in a blue moon, firewire connections are faster, as pc's really weren't technically made for firewire capture, when it first came out, so they are somewhat behind in that respect..
the amount of software you might be running at once and how the mac handles resources aren't even able to be compared back and forth.
On a pc, sure you could run vegas video or premiere pro, and a few other apps, but eventually the system is going lose resources perhaps have a memory dump etc. I mean honestly its inevitable. I normally run 10 or so apps at once on the mac flawlessly. I can go from rendering in Final Cut Pro, which basically is a huge reason to go mac b/c of how great the software is, but I could jump into after effects, or photoshop, have itunes open, as many browser windows as I want, live type, while I'm checking mail, chatting, etc...
I do have a pc right next to the mac, for certain things that the mac can't do yet, like using windows media encoder, which they need to make for the mac already! But, honesetly I bought a dual g5 and I don't even look back. Was the best purchase I ever made. And seriously, being able to upgrade to 8 gigs of ram, that really can extend the life of this system. I personally, don't think I'll have to even look at slowing down, or needing a new sysetm for 4 or 5 years at this point.
And I'm sure by then I'll have made the investment back on this G5 many many times over.
