..and iMovie won't use all those cores in the MacPro.
Do a nice After Effects render and you'll see a big difference when it fires on all cylinders, or use a program or plug-in that is GPU-accelerated, then you might also appreciate the Mac Pro's ability to work with ATI 4870 cards, etc.
But if you don't do any heavy lifting and are happy to import footage via Firewire or USB, then the iMac will be fine.
[B.J. Ahlen]"But if you don't do any heavy lifting and are happy to import footage via Firewire or USB, then the iMac will be fine. "
First off the new iMac 27" is capable of doing some serious heavy lifting with a LOT of RAM and an ATI 4850 Graphics card.
2nd, Firewire and USB are not your only options. We run an Ethernet SAN here and one of our iMacs is cutting on a documentary with over 200 hours of raw 720p / 60 ProRes material. It's performing so well we're going to outfit some of our new edit suites solely with the 27" iMac.
It's not just an afterthought anymore, this is a very very good production machine now.
Walter Biscardi, Jr.
Editor, Colorist, Director, Writer, Consultant, Author. HD Post and Production Biscardi Creative Media