A few years back iMacs were really only good for web browsing, email, and media storage. A lot has changed in a few years. The iMac is still a beautiful piece of hardware. It's a big screen with brains, and looks as good as it performs. But now that you can get them with the i7 processor and up to 16GB of RAM, not to mention the display screen that makes me want to put on sun block... Mmmmm Mmmmm Mmmmm! These things are a serious competitor to the Mac Pro for the hearts and minds of most Creatives and Designers.  

Have no fear pumping Adobe Photoshop or other similar programs through it's circuits. With the new i7 processors and stock 4GB RAM, the iMac easily handles most tasks without a hitch. It can also handle a moderate amount of basic video editing and animation. For the big stuff though, you'll need the Mac Pro.

A completely pimped out iMac will run you around $4200, with the 27" base model costing $1700.

The MacPro (or Franken-Mac as I like to call them) are truly awesome machines. You can get these things with up to 32GB of RAM!  That makes me laugh... I rarely come close to using the 8 gigs in mine, but that doesn't mean I can't appreciate big numbers. With the Mac Pro you get many more choices for drives and other upgrade options, so the platform is more flexible.

These machines are best suited as a dedicated media editing system, or a robust design rig. Having the ability to switch between Photoshop, Illustrator, AfterEffects, and Premier Pro on the fly, without issue is a magical feat. They are capable of handling just about any creative program on the market. Just be prepared to to shell out the $$$. Oh, and you have to purchase the display separately.

A totally tricked out Mac Pro runs a whopping $17,318, with the base model Quad-core starting at $2500.

Here is a quick rundown of the pros and cons for both:

iMac
+Fits the needs of most Creatives and Designers
+Low power consumption.
+Value
-Not optimum for editing video
-Won't make you breakfast

Mac Pro
+Extremely flexible platform
+As fast and powerful as you want (or can afford) to make it
+longer life-cycle
-no monitor included
-Won't make you breakfast either