I'm sure this has probably been covered... and I'll do a search, but I'm kinda pressed for time so I'm throwing this out to the group. Short and sweet: My average daily computing consists simultaneously of RIPPING/BURNING CDs, Playing iTunes, having email, chat and web-browser open, half the time I've got WoW on an extended display and a few times a week of manipulating photos with PS Elements. I tend to watch a lot of video (streaming) as well. On Anandtech I read that with the mac pro in single threaded applications, I can probably expect the system to perform similarly to a single dual core chip. In well multi-threaded applications, I'd find significant higher performance (dual dual core vs. single dual core). My fear is that even with all I do above that I may not be crossing the barrier of necessity for a dual dual core system. Spending much more than necessary. Know what I mean? What type of multi-threaded applications do I have to be running to reach a point where it makes sense to run multiple processors? I'm not knowledgeable about which applications are well multi-threaded or not. I'm on a 20" iMac now and while I love it, I also know that it's not a machine with enough power for me. Also, I recognize that upgrading to the iMac 24" may serve me well today but is no where near as upgradable as the Pro system. But, you know, if I'm simply not going to cross-over into a real where dual dual cores are necessary it may be a waste. The problem is how does one determine this, you know? Maybe in a year from now there will be more "everyday" applications that require or prefer multiple processors. Help.