Heh...quantum computers may come along sooner than you think. An estimate I saw about three years ago put them at 10 years out.
Regardless, remember that there are a large number of technologies on the horizon that could dramatically improve processor power for more traditional systems, including MRAM (which will be much lower power and may be higher-speed than DRAM, aside from its non-volatile nature), and non-silicon semiconductors. There's a ton of research going on in these fields right now.
As a side note, I recently saw a presentation by a physicist talking about a new substance that, while there are apparently significant manufacturing problems, is capable of in the range of 1-10 Terabits per square inch (most of the presentation centered around a computational method that was much better at determining the magnetic anisotropy than the more standard methods).
"Physics is like sex. Sure, it may give some practical results, but that's not why we do it." - Richard P. Feynman