To summarize, $150 and above for the CPU is the price where Intel simply dominates the market in terms of performance. I consider this the upper end of low-priced/low end of mid-priced computers.
This refers to the P4 2.4 ghz 533 fsb beating the slightly higher priced Athlon XP 2800+.
Everything under this price level is AMD's share of the market. As priced on
pricewatch.com, the Athlon XP 2700+ is $126, which beats P4 2.0 Ghz chips and down (price and performance). Everything at this level is low to extremely low priced computing, not counting the second-hand market.
In case you're wondering how the $86 2.4 Ghz Celeron stacks up to the to XP 2400/2500+ (similarly priced), it doesn't, so don't bother.