For high-end machines, I've seen articles showing they are comparably priced, but those articles tend to forget that the mainstream PC makers offer discounts all the time. I don't think I've ever seen a real sale on the Macbook line (and a free iPod touch or whatever they decide to bundle is not equivalent to getting a discount worth the MSRP of the bundled device), while Dell, HP regularly have large discounts on their machines and the retail stores have sales every week. Taking that into consideration, the cost of a PC is a significantly less.

You still have to consider which market you're catering to. The concept may not work for a power-user, but for someone who finds the plethora of options confusing and a detriment, that concept may be just fine. How easily we always forget that the majority of users aren't ./-ers.