The glowing slot on the Revolution sounds like a mistake, unless there's a system for dimming it. Too distracting, same with the X360 logo, it's there for show but not functional when standing next to the set. Otherwise, I like that design.
The PS2 has always been a personal favorite in terms of stark elegance, the Revo takes that same concept and gives it even more style ... for some reason, though, it looks more faceless than PS2 to me and not as interesting. From the side, a piece of work; face on, I like PS2 and the new mini PS2 better, and I especially like the automotive color PS2s for pure style.
PS3 and Xbox 360 are too busy, from what I've seen. I haven't seen one on a desktop, though, so maybe the style comes across then. 360's faceplate was a very clever invention.
Old consoles ... hard to find one that's not beautiful by nostalgia. Certainly not PSX or N64 or DreamCast, not SNES or NES. Genesis is sharp for way back when style. A few Japanese-only consoles have some lasting style.