Yep. That's a static wallpaper from Smashing Magazine (a very useful website).
I think it's the more deluded art students and wannabes that think they have to have a Mac for design or new media work. And you're right of course, Creative Suite, for example, is functionally exactly the same on Windows and OS X. I'm not qualified to comment on the differences in how the OSes handle virtual memory and image caching; it may make a small difference to execution speed, especially when you're editing 200MB+ .PSD files.
Emulation for the Mac is dismal. Power64 is great but you have to pay, and E-UAE is derived from WinUAE but it lacks a decent front-end (although there is Hi-Toro) and I've never had it running as well as WinUAE on a PC.