Egg, what's heavier? A tonne of coal or a tonne of feathers?

An inch is an inch, be there 72 pixels in it or 96. If you make a 1 inch by 1 inch square in Xara it will export at 96dpi by default. If you change it to 72dpi the image will be smaller, so no longer 1 inch by 1 inch. How then, can that image be 72 dots PER INCH? The dpi has no bearing on the size the image appears on screen.

All the wallpapers on my website are 72ppi and they will fit anybody's screen as they should do. An 800x600 wallpaper will fill an 800x600 resolution - it will not come up smaller.

I agree with you that if you create an image in Xara and want it to be the exact same size on your website, then you have to export it at 96dpi. However, the original question was what is best for the web, 96 or 72? The current standard is 72 because they will download quicker and use up less bandwidth - key points when it comes to web development. Granted, the difference between 96 and 72 is probably marginal, but the standard is still 72.