If you have used the new Celeron D 775 socket before, it is a huge improvement on the old design. Basically, it is nothing but a earlier model P4. The specs are the same as what a P4 used to be, and very cheap.
I still prefer a Sempron over a Celeron though. To me though, it seems stupid on AMDs part to sell a proc not far off in performance from the Athlon. I don't think I would ever buy a Athlon now with the performance I've seen come from the Sempron at a much lower cost.
