I started on the Mac platform with a consumer level machine back in the day, and quickly moved up to the pro end from there. I loved my Power Mac very much, but when the time came for me to upgrade last October, I broke my own rules and went for the 24" iMac, and this is why:
1. Intel. Every Mac made at this time is very fast, and in my experience, is faster than the same hardware in Windows. The gap between performance in the iMac or the Mac Pro was really minimal unless you are making a living off the highest end video or 3D apps. In fact, when running typical software, the iMac actually has a speed advantage. This made the Mac Pro a lot more expensive for negligable performance improvements for all but the most demanding users.
2. The 24" iMac. I had to take a long hard look at my computing needs, and when I did, I discovered that because of the Intel upgrade, my needs fell clearly into the "prosumer" range. The 24" iMac provided a very good graphics card, nice storage options, a brilliant screen, and the means to high speed external storage through Firewire 800. A 3 gigs of RAM ceiling and a potentially upgradable gfx card were icing for me. For the first time ever, Apple had put together an iMac with enough features and power to finally bridge the gap between pro and consumer, and do so at a reasonable price point.
3. Design and consumer link. The iMac is compact, stylish, and even semi-portable if you are in a bind. One of the nice things about it is that it is still linked to the consumer market, making it a focus of all kinds of aftermarket goodies. It is a small thing, but it has some nice benefits.
If you MUST have the latest and greatest gfx card, you don't want the iMac. If you are rendering 3D or HD video all day, you probably want a Mac Pro. If you want to run the hottest games on the market at high quality for the next 2 years, you probably don't want a Mac at all. Otherwise, an iMac, and specifically the 24" will likely surprise you with just how capable it really is...
