Hmm, the SSD is a good point. I don't think my interactive desktop usage is very often CPU-bound, which is one reason I don't notice much difference between the older and newer machines I own. But an SSD might make some difference, because I'm guessing some stuff (esp. app startup) is I/O-bound.

I do often take a software approach to speeding things up, though. For example, my solution to Firefox taking a few seconds to start up was to switch to Chrome. ;-) And thanks to the amazing JS compiler advances over the past few years, my old laptop runs JS much faster today than it did when it was new!