Well the real deal will be multiple dual cores on one board, like a quad of dual cores, aimed at the high end server market, dual dual cores for midrange servers and high end graphics stations or rendering farms.
You can do dual athlon MP's for what like $350-$400 these days?Dual Xeons for a little more, they get the price within a few hundred bucks of that after a few months of production, being 64bit, it would definitley be worth it.
Multiprocessing is going to have to be the next step, heat is becoming a huge problem with single cores, so is scalability.Die size is also limiting things too, as well as micron process sizes.
I d like to know what the power consumption is gonna be like, and how much longer till the low power CPU's start making an impact with desktop PC's, I cant see any huge increases in single core CPU's coming anytime soon unless the heat problem gets solved first.
Then what about 128 bit or 256 bit cpu's, that cant be too far off at the rate things are progressing.