I agree GNOME and KDE are quite ugly (even with different themes) ... my recommendation: fluxbox
I've recently decided to try out nearly every window manager available for Linux, including: GNOME, KDE, Fluxbox, Blackbox, Afterstep, IceWM, Openbox, WM, XFCE
I say fluxbox is the best ... the ugliest being GNOME, KDE, XFCE, IceWM
Now .... there are usually downsides to having transparency effects, like increased resource usage ... it doesn't seem to be the case with fluxbox ... can't say the same thing for Vi$ta. And Vi$ta is far less customizable, stable, useful. I switched away from GNOME mostly cuz nautilus kept crashing and GNOME in general kept not responding (keyboard not responding), which never happened on KDE BTW and neither on fluxbox.
Now whether Vi$ta is a rip-off of OS X ... that's almost guarranteed, but of course there are ingnorant people out there who refuse to take into account any evidence whatsoever in making a case for this ...