MC360 is a great replica skin but IMHO it cant be used as a media centre skin simply because the way its designed and the way the icons have limited space on the right hand side, but its still a great skin but not for my every day video watching pleasure, other people might disagree but thats just me.
Blackbolt Classic is a wicked skin as well and its the smoothest working skin of all the skins available, to me I just regard it as the default XBMC skin neatly designed and looks very nice as well, I just dont use it that much maybe because I dont fancy the way the menus are.
PM3 Is the First skin I ever used and If I want to check any thing that I'm not sure about its the skin that I'm going back to any time.
Slate is cool but needs some fixing.
Xtv If there was no Clearity I would've used Xtv as my default skin, but some of its themes are lame sorry
PDM I used it just once
looks like a PM3 Morph.
Vision I just cant wait to play with this skin and I think its just gona Rock.
Clearity where My vote goes. Its Simple, Clean Interface, Very nice, I love its design and the way it presents the Media Info.