Scott,
First a few words about platforms...
In the 6 years I've used macs for professional photography / design. I've only had one data loss crash. I have one monthly on the PC system I use here at the studio.
As far as costs issues, if you configure a Dell with the EXACT same details as a Mac you will find the actually cost much more. A mid level Intel Power Mac is $1000 CHEAPER than the DELL version.
Aperture is an OK program, like others said it is not a Photoshop replacement. Iview media is ok as well for a catolougue program. Both however affect the integrity of the image data, that is they alter to their specs for processing, file naming, etc. This is a big deal as who knows what information they are deeming acceptable as throwing out.
I would stick with the Adobe CS2 suite and upgrade to CS3 as soon as it hits in Feburary. Adobe has a program similar to Aperture called Lightroom, I've been beta testing it for almost a year now and its great. You get the file management, easy RAW processing, good colors and seamless integration with photoshop. If you decide to get a Intel mac you will need CS3 as CS2 will move super slow dues to the new OS.
Hope that helps.
Justin