The speed difference between Vista and XP is noticeable, with XP being considerably faster, and the gap is about to widen even more: Early in 2008, Microsoft is planning to release Service Pack 3 for XP, and I have heard that SP3 will, for example, make XP running MS Word 10% faster than XP with Service Pack 2, widening the speed gap considerably. (I'm not sure what the speed comparison would be when running Amiga emulations.)
Vista may or may not be a complete turkey as some claim--I suspect it will take a couple of service packs to know for sure--but there seems to be no compelling reason to upgrade to Vista on an existing computer unless you are both (1) a hard-core gamer who frequently upgrades or a high-end graphics user and (2) you have a Direct X-10 compatible graphics card (or cards) in your system. Getting a new computer with Vista would seem okay, as long as you don't get Vista Home Basic and get either Home Premium or Ultimate.
In issuing Service Pack 3 for XP, Microsoft is clearly on the defensive. It's nice to see them at least somewhat on the defensive for a change.
