My AMD 700 box is dead (bad motherboard, will not boot with PCI card; ex. NIC).
I replaced it with an AMD Athlon 64 2.0GHz Venice on an Asus A8V with 1GB Corsair XMS3200 TWINX.
Nice upgrade. My problem with uprading my PIII is that I don't have a legal OS to put on it. That means I have to go Linux and I'm over my head.
In any case, if I do upgrade, the word on the street (Anandtech)is this is the best value for the buck/speed trade-off.
http://forums.anandtech.com/messageview.aspx?catid=40&threadid=1796551&enterthread=y