> would KDE really be that much of a [burden] to my system?
Absolutely not. I think my absolutely largest memory usage is at 512 mb, and that's only after leaving various big and leaky programs open for several weeks; also, some of it is swapped out. CPU-wise, the only thing I've noticed is that firefox is somewhat faster than konqueror (IIRC; it's been a while since I've last used firefox).
Try it out--you can always go back if you don't like it.
> in a [sense] that on old systems emacs might be a huge hog but on modern systems 8mb memmory doesn't matter at all?
Something like that. My experience is that vi starts considerably faster (0.1 vs 1 second), and both operate at "wire speed" once started. Eric Raymond has some comments at http://catb.org/~esr/writings/taoup/...emacs_editing;
I would bet that a modern vi-like editor (that is, vim) uses about the same amount of memory as emacs.