And for those overclockers on a budget

It seems everone has jumped on the s939 bandgwagon, however the 90nm 64bit s754 semperons seem to be doing quite well on the cheap. These CPUs probably aren't for everyone though. If your requirements include cheap highly overclockable and you don't mind single channel memory this could be the platform for you.

Some results including 100% overclock on air.
2800+
http://www.xtremesystems.org/forums/showthread.php?t=80159

2500+
http://www.xtremesystems.org/forums/showthread.php?t=87658

You can pick up the CPUs for $75 or less with 256k cache from newegg.
http://www.newegg.com/Product/ProductList.asp?N=2000340343+1050717289&Submit=ENE&SubCategory=343

Then as far as motherboards go this is where the real suprise comes in. The best motherboard for these CPUs isn't the DFI lanparty NF3 250GB but the Biostar tforce6100. The reason being these motherboards allow a max HTT of 450 where the DFI lanparty maxes out at 350. If you want to use your high voltage loving memory this thing offers 3.3v for ram and 1.8v for the CPU also. Best part of all these suckers are cheap like $70 shipped form newegg.
http://www.newegg.com/Product/ProductList.asp?N=2000340343+1050717289&Submit=ENE&SubCategory=343

I own a DFI myself (see rig)

This baby could reach 385HTT... And it's WAY more stable

I currently have a s754 sempron system. If you use Asus boards get anything higher then a sempron 2600+ as they dont support cool and quiet and therefor no voltage or multi settings on asus boards.

But I have to aggree. I had the 2600+ and I currently have a 3100+ and they are very overclockable and rock. These chips are great on the cheap and overclock well as well as provide excellent performance.

I would still take a Claw or preferably a Newark over these.

I've got sempinized, except my OC is kinda droppin... i'm gonna have to do something about it.
This NF4-X infinity has a max HTT of 450 as well, but i havent tried anything above 310 since i'm gonna have to pump my chip full of voltage
These are the kinda OC's i was dreaming of lately after i saw a 2600+ do 3.2ghz