Faster, better, cheaper: what is the true value of a computer?

One thing I've had a lot of time to think about over the last 15 years is what exactly does faster & more powerful mean? After a decade of clockspeed wars, we've moved on to more cores, more RAM, longer battery life, less weight, backlit keyboards, etc. A new computer still costs about the same as it did 15 years ago... is it any better?

The more time I spend with the machines, the more I think about usability. A machine is only as powerful as the tasks it can accomplish. I have a $200 netbook (w/linux, of course) that excels at being light. It works great for travel but not netflix. I could not write a paper on it, but I can check email, upload photos/files, etc.

In our computer cluster here, we upgrade as we hit limits. Ran out of RAM? Buy more... it's cheap (for a desktop, at least). Chronic, awful wrist pain? Get an ergonomic keyboard. I find a 2-screen setup a very cost-effective productivity boost, whereas the idea of paying 20% more for a 10% bump in speed strikes me as silly.

The whole state of affairs reminds me a little of mean and variance. We always hear about the expected values of things, the mean, but rarely is variance ever reported, and variance is often the most important part. Things like weather, lifespan, salary, time-to-completion? The variance may be more important than the mean. Speed/power tells something about the "maximum potential" of a machine, but not how much use one might get out of it.

I see two different directions --

First, unexpected developments. Examples include multiple cores and SSD. No one really expected these to change the aesthetics of computers. Nonetheless, the reduced latency of SSD is pleasantly surprising, as is the increased responsiveness under load of a multi-core machine. I don't hit enter and wait. My machine flows more at the speed of thought than it used to, even if I have a browser with 50+ tabs open, music playing, etc.

Second, human interface. My new phone is just a little too tall, which makes it just a little more difficult to use, since I can't reach across the screen with one hand. Again, I never expected this to matter, but it's a human-machine interface question rather than a pure machine capabilities question. Backlit keyboards, ergonomic keyboards, featherweight laptops, and long battery lives are all about the human-machine interface. Which is more important than speed, since the human is the whole point....

The aesthetics of interface is how Apple came to rule the world. Their hardware is beautiful, intuitively responsive to human touch. Hell, even their stores are clean & informative and intuitive and full of fun toys. Personally, I can't stand their walled-garden approach to hardware, and I have the time and energy to coax my machines into greatness through a commandline interface (which remains one of the most powerful human-machine interface ever developed), but I *like* Apple hardware. They've dragged the PC industry kicking and screaming into the 21st century of "Humans matter more than machines".

Which they rather presciently highlighted in their 1984 Superbowl commercial:
http://www.youtube.com/watch?v=2zfqw8nhUwA

Finally, a mind-blowing historical view on the subject, including a 1983 Bill Gates pimping Apple hardware, and Steve Jobs describing how machines should help people rather than the other way around:
http://www.youtube.com/watch?v=xItV5U-V2W4