I have to disagree with the basic idea of this thread.
I just bought a new motherboard for the newest Intel cpu (P8P67 Pro) and it was $189. It's not their most expensive board but it has a lot of extra features and it performs extremely well.
So let's look back to the past.
The very 1st purchase I ever made from Newegg was on 11/13/2001. I bought the MSI K7N420 PRO
Newegg.com -MSI K7N420
And it was $187, this was a top tier mobo at the time but it had no where near the extra features you expect today.
In todays market we do have $400 motherboards but they offer manufacturing quality and extra features that were unheard of 10 years ago. There was no equivalent class of motherboard 10 years ago to compare them against.
And looking thru a few more of my Newegg invoices it seems that memory prices are still about the same.
All in all I'm still spending about the same amount of money for a whole PC as I was 10 years ago.
And it doesn't matter which Platform your building from. Right now an Intel system is more expensive but they have the "fastest" systems. A few years back (9/4/2005) when AMD had the "fastest" systems I bought the X2 4800+ and it was $884.
Newegg.com - AMD Athlon 64 X2 4800+ Toledo 2.4GHz 2 x 1MB L2 Cache Socket 939 Dual-Core Processor ADA4800CDBOX
When AMD's new cpu comes out, if it's an Intel Killer, it will be priced accordingly also.