Well im not much of an intel guy, but i can help ya make sense
If a celeron D is faster than a normal celeron, im guessing their 256k cache instead of the 128 on the normal celeron. I also heard that celerons are a p4 - something, like 256k of cache was broken on a p4, so they disabled it and called it a celeron.
Barton cores are the old AMD core, used in mobiles and for some OC'ers, not worth considering any more.
Presscott is intel's new core, very hot