I work in my university's computer support department, so I work with both PC's (of ALL makes and models) and Macs on a daily basis.
The best analogy I can make about Macs is that they are the Mercedes of computers. They're expensive, non-upgradable, not
*incredibly fast* and full of proprietary hardware/software. Simply put, inter-company competition simply does not exist in the Apple world. Like Mercedes, they charge whatever they want for hardware and O/S's, and people will pay it, because the Mac-heads don't have any other brands to choose from. (Apple DID have third party hardware manufacturers like Power Computing a few years ago, which was their smartest move as an underdog, but they since killed that program).
Competition in the PC world is *everywhere.* Intel and AMD are always going at it, making processors faster and cheaper every week. The fastest Mac processor is 1 ghz. To buy that **processor** alone (
from a mac store) is $789, whereas an AMD processor more than twice as fast costs only
$200. Simply put, there are *hundreds* of brands of PC hardware and software available, so the PC market (even parts that can be added easily to a Dell, no differently from any custom PC system) is far more comprehensive, and CHEAP, than the Mac market.
Falcon Northwest makes some fabulous computers for the mid-to-high end market. They even have a feature called the Mach-V Exotix, where you pick any car by any manufacturer, in ANY year, and they'll paint your computer case with a full automotive finish (clear coat and all, you can WAX your computer if you want). I'd take a 99 Civic Si Electron Blue, pls.

Take a look at this "Viper Chameleon" finish.
click for a bigger image
Alienware makes some very high quality systems as well. They sell these at Best Buys now, too, so I've heard.
Dell, as you mentioned, makes some great systems too. We use those in most of our labs at school, and they get beat up on a daily basis; they're still all going strong. Dell's support is top-notch, if anything breaks, they'll send you a new part right away.
Finally, I recommend
Mwave as an alternative manufacturer that can custom make a very high quality computer for you *to your specifications* for a price less than you'd pay at any of the above 3 manufacturers. I've built six computers through them, and haven't had a problem yet. They usually do same-day shipping too.
Good luck, and let me know if you have any questions.
