rd2002

i think e4xx0 series is better because l2 cache is bigger than the e2xx0, even though there have been some reports saying their performance is about the same.
like cck_my said in the previous entry, pentium d is the older generation intel cpu. it is only a dual core, not duo core, meaning it has no REAL 2 cores to process. it will be outperformed by either e2xx0 or e4xx0 series. just want to mind you that although e2140 uses the product name of dual core, it is a real duo core cpu.
in addition, if you are thinking to get more out from your cpu, aka overclocking, the newer line of intel is a much, much better choice.
so, don't be fooled by your friend~

rd2002

actually, if you don't want to wait, go ahead and shop at ebay.
there have been lots of good cpu are flowing around there. and the price is excellent as well.
but, the only thing you gotta pay attention is that you have to buy new and boxed cpu there because i don't think oem cpu is a good option to you, given the price is similar.