To play the latest games you don't need a 3.06 P4. Just make sure you got a good graphics card and lots of memory. Wait fro the 5900FX to get cheaper which supports DX9 and away you go when games are written with this platform.
"considering the speed and reliability of modern processors your decision really (in my opinion) should be based on what motherboard you want, whether you want RAID ,how many usb ports firewire ports etc. find the best motherboard with the chipset that supports everything you want then your choice of processor will be made for you. truth is if you want the best then an INTEL based board with an Intel processor is the wisest choice and with an 800Mhz FSB you wont beat the speed. look through the old posts here and you will see that the majority of hardware related problems involve AMD processors and VIA chipsets which are not as well integrated as their intel counterparts. also good software is written to take advantage of the internal architecture of intel cpu's. but hey AMD make a mean machine at a good price so like i say base your decision on the motherboard you need not just on the processor"
if you can afford a P4 3.06 with 800Mhz FSB with hyperthreading then thats the machine to have.