You've been happy with XP on a vintage machine
...and also happy on the self build with WIN7 on which I am typing this, but I only have limited access as its been comandeered to feed UK television to the living room TVs until I upgrade to a 2m20 dish.
Of all the OS I currently use I prefer Android, but I am too busy to cobble something up for my PCs.
The suggestion of John Lewis is one I had not considered, but buying televisions there for use in the UK has always been a satisfactory experience.