I think the 400Mhz CPU's are better for overclocking purposes.
I am like you Deja. I only have that one system I overclocked, just to play with it. The dang thing is stable as can be. Hehe,..a 600Mhz gain in clock is not what I call trivial. But I do have to say, I think Intel messed up on my CPU. It says it is a 1.8 on the chip, but when I stuck it in the system, the BIOS detected it as a 2.4Ghz.
From there I bumped the FSB.
Now, my 2.5Ghz/533 bad boy, I have left at stock and will leave it at stock.
Vermillion,..the Intel's are more expensive, but the one thing I really do like about the newer P4's is how cool they run. Allows a very quiet case, without resorting to water cooling.
Personally, I just have not seen the problems with Intel chipsets that I see with other chipsets.
I think AMD's are great for the tinkerer, and the guy that really knows his stuff, and I approach Intel as the basic thing a guy should use if they do not have a clue about hardware or just do not want to fiddle with it.