Speaking of computers feeling fast (and me agreeing that the OS is key as software almost always fail to fully leverage the hardware), have any of you noticed that Windows XP (SP2) has become very sluggish as of late (probably some update)? I am talking basic window creation and destruction. Especially Internet Explorer seems to not close windows as fast as it once did, sometimes not responding to the close window command at all (clicking the red-white X). At first I thought it was particular to my main workstation, but then I saw the same thing on other PCs as well. I dunno, it just feels like the GUI is lagging badly some times. I have always been annoyed with the lag when sometimes you select a file, press delete, followed by a quick enter, and end up launching the file instead of sending it to the bin, but now it seems this has spread everywhere in the system.
Give it a try. Open a few Explorer windows (including or exclusively IE) and then try to close them as quickly as you can by pressing the upper right close window widget. Sometimes it stalls for over a second for me, prompting me to hit it again, then closing and having a second click 'buffered' it then closes the window underneath as well. Very annoying.
If the OS was more or less perfect, I think it's fair to say that besides a fast processor, a fast hard disk and lots of RAM helps keep things feeling snappy.