The only reason I'd consider going for a Mac is for the look. But given that a Mac would cost three times the amount of my current PC (which is no fossil), it's hard to justify. I'd probably just blow the $1000 difference on a ATI Radeon and a custom case + accessories. Mac's security advantage? Not really my concern since I use a combo of Linux and a properly secured Windows. If Apple ever becomes more competitive in terms of pricing though...
Lessee... Apple 17" iMac = $1300 divided by 3 means your system cost you $433.
Does that include a 17" Widescreen (16x9 aspect ratio) LCD monitor?
Did you buy a copy of WindowsXP or did you use one you already had?
What suite of software do you include with your $400 wonder?
Does it include a waranty?
Did you build it yourself?
As a person with 5 Macs I can commiserate with you about the price. That is why, even though I love my Mac, that I never try to "sell" it to other people. But, when I have taken my Mac to work, the young 30-something males think it's great ... they love the display, bells and whistles. But they always shy away from the price, alas.