I wouldnt say I have nostalgia for XP itself, but I do look on it fondly, the same reason I look on 98 fondly.

It was better than its previous OS. More stable, more usable, requiring less reformats to keep it snappy and healthy, etc.

Which is one of the many reasons why 7 is the peak. Cause you didnt have to regularly reformat 7. It was just that good at managing itself, and its snappiness, that you never had to reformat/refresh the install cause it never got bogged down.