This marx the end of an era, the era of single core. Long Live multicore!

And these new Sempron models don't even correspond to Sparta, unless they added an extra 256KiB L2 last-minute to make the part needlessly more expensive. Whatever, I give up trying to figure out what's up with Sparta... I certainly hope it will be ready for the OEM cycles at least, whatever it may be, ffs.

Does this make my current processor a rare collectors' item? Should I hold on to it for five more years and then sell it for huge money?

In any case, this may just be another excercise in rebranding the same product. What is an Athlon 64 now may be a Sempron 64 in a few months, but that doesn't make the products any different.
It might make sense if AMD tried to rid itself of the "Athlon" brand, on to a Phenom/Sempron split. It's an old brand, and even though it was very successful people might remember that "Athlon has been beaten", which isn't the image one wants to have associated with a new high-end line of new product.

from the title I'd think AMD stops single core PC CPUs altogether, but really it's a case of naming. Semprons are just Athlon 64.