If you need to do some heavy work then an older system obviously won't do. Editing files with Vim, on the other hand, works just fine with something like a Core 2 or Pentium M.
Everyone's use case is different, but in many cases, older hardware simply isn't a limitation.
Absolutely, I just used Deadline for writing and light diagramming. As a bonus I actually liked Win2k, it was stable and didn't get in my way. The only thing it was missing was font smoothing.
Everyone's use case is different, but in many cases, older hardware simply isn't a limitation.