Like many, I forewent the upgrade to Windows Vista once I realised the problems it was causing others - although by that time I had bought my wife a new PC, which came with Vista, so I was experiencing those problems for myself. Therefore I stuck resolutely to my old machine until Windows 7 appeared. As a result, by the time I took the plunge, I was upgrading from kit bought in 2006, which gave me a good excuse to get something with Windows 7 already installed, rather than fork out for the software and then go through the hassle of finding drivers for out-of-date hardware.
That said, my old machine did have a reasonable spec, running Windows XP Professional SP3 on a 3GHz hyper-threading Pentium 4 with 1Gb of memory and a 60Gb hard disk. However the hard drive was beginning to chunder for long periods for no apparent reason, and I could go and make a coffee while waiting for Adobe InDesign to load a document.