A Tale of Two 'Puters
I am sitting at my desk with my Mac on the left and my Athlon Box on the right. A 20 inch screen on my left and a 19 inch screen on my right. Thank TPTB that flat panel displays are so damn good. I'd have no desk space left were I running with CRT monitors.
But it's not just deskspace any more. I have two wireless keyboards and two wireless mice sitting on my desktop too. And I switch between the two platforms (right now the PC is running Firefox with an attractive brushed-metal looking theme I grabbed when I downloaded the browser yesterday) with most of the real work going on to the left (natch). But it's weird to juggle two mice and two active keyboards. You should try it sometime just as an exercise in unconscious memory. Are you able to put your hand on the correct mouse every time? When you switch machines, do you start typing on the wrong keyboard? It's not easy.
Now that I have a direct side-by-side comparison, I can satate with a high degree of confidence that Firefox on the Mac is preferrable for the small but distinct advantage of having a "Window" menu.
I visited Sugarmama this morning and made a comment - OK, a couple of comments - but I wanted to double check what I was commenting so I clicked on the browser window. The comment window was then lost behind the main window. On the Mac, I only have to choose the comment window from the Window menu. I am unaware of a way to bring the window forward as easily on the PC. It's probably there but I'm unaware of it. So the Mac version is preferable even if only for my limited experience on the PC.
But really, don't you want a Windows menu on your PC?

The other salient aspect is fan noise. My iMac is dead quiet. I can't say silent because there is a smidgen of noise (like optical drive spinup) but the PC is ever in the background with the fan. Think what you will of Steve Jobs but the design he pushes (even the desktop G5s are designed with cooling zones to minimize fan noise) is superb.