As for me I like that in XP interface must looks like classic window and button style like in Firefox / CuteFtp /eMule and so on . It will be nice, if skins are difficult to use simply ask before installation which interface do you want to use . :-TU
I would like the option to use classic skin/no skin/current windows skin also !
CIS is currently the only application (that I am using regulary) that does not have such an option.
It would somehow just look more “pro” if it had one 
I’m not even certain why security software even does something like skinning. It’s just more code to look at and maintain. IMHO security software should be written using the KISS principle and have as little code as possible to reduce the possible footprint for bugs. I can always use something like WindowsBlinds to skin my software if I really wanted to.
I would like to have an option to disable skinning as well.