It's nice to have a poll, but I find it better to hear people voice their comments about their answer.
Here are my comments, you are all welcome to voice yours in this thread.
Personnaly, given the way the question was written, I had no choice but vote for #1. Windows customization is indeed getting more popular, there is no denying it.  But I could have just as well have answered #3 if originality and quality was concerned.  It is my opinion that the days are long gone where skinners were trying to be original, come up with new imaginative ways to have things look and feel. I guess, that's what happens when skinning gets a bit more mainstream (although it's still not really completely so either - read last paragraph): skins become more conservative. Oh, there are still lots of very nice looking skins, but very few daring ones. 
Also, while I do agree that more and more people are getting into customization, I'd like to mention that it's still a small niche. I think it's still a very long way before skinning (or customization) come to the masses - if it ever does.  Don't forget that most computer users don't even know how to change their friggen resolution, let alone start applying different skins! 
My two cents. Here, your turn now.