From 95-00, the jumps were huge, you're looking at the original non-MMX Pentium to a 1.5Ghz Willamette and on the graphics front something line a 2mb Trio to a Geforce 3/ Radeon 8500. But IMHO I think the momentum has never slowed down, nor the jumps been smaller with each new generation.
From 05-10, what have we? Athlon 64s were the bomb in 2005, available in FX guise, dual core and capable of overclocking up to 3ghz. Coupled with an NF4 chipset, 1gb ram and let's sat ummm, a GF6800GT or 8xx series this was potent combination 5 years ago.
If you are using this for any non-gaming task today it would still be mega fast, but unfortunately such a system is not capable of playing any of today's games (besides Torchlight) with a reasonable amount of eye-candy on.
So now 5 years on the standard setup for a reasonable gaming rig would be any garden variety quad core, 4 gb ram and something like a GTX460/ 5850.
Compared with what we had 5 years back the available technology is a quantum leap ahead. And necessary if you intend to enjoy today's games the way the developers intended. But if you're not gaming then I think a P4 would still be plenty for most people.