I don't really like the CTS-V sedan, but I love the V coupe, which is why I own one. As far as sedans go, the M5 and E63 are pretty far above the CTS-V in terms of styling.
Between the M5 and E63....that's a tough one. The M5 is underwhelmingly understated, but still has beautiful lines. I can't wait to see more in white, especially with aftermarket wheels.
The E63 just has a boss presence, however people that don't know how special it is just look at the car as another vanilla benz.
The CTS-V has a design language that just translates better into coupe form, and the coupe is truly stunning in person. Honestly though I'm selling mine as soon as this new M5 hits, a BMW TT V8 is pretty much too hard to not consider. It's true what they say, once you go BMW, it's hard to go back
Winner of this comparo, and the 'I want one' contest=M5.