what is the best chip in a pc ? is it celaron d pentiuim 4 please can someone tell me thanks?

By spooksthe duo core 2 should be released in the spring. It would make much more sense to wait until it is released with Vista unless you desperately need a computer now.
AMD FX 64
I'd have to say the XEON dual-core or Opteron dual-core. But, for most of us it must be the Pentium D or AMD X2. For the money, I'd say AMD.

I would not waste any time on celerons or semprons. They are fine for business apps though.
intel core 2 duo

least power usage and very fast