Wool seems to divide people into those who love it and those who hate it. I love the stuff and use it whenever possible. All my winter accessories and sweaters have some amount of wool in them. Before you decide I'm crazy or have no sensation in my skin, let me explain why I love wool.
The most common argument against wool is that it's itchy, scratchy, icky to wear! Well, it is and it isn't. Some of it is - the cheap kind is the horrible scratchy stuff. Because it's cheap, it's what is more commonly used and seen (felt?) in non-handmade items, and I imagine that's where the impression of "wool = itchy" comes from. I can't stand that stuff either. Also, cheaper wools may have been treated with harsh chemicals, which irritate sensitive skin. But all wool isn't like that - soft, high quality wool is something different altogether and this is the stuff I love. In between the extremes are all kinds of levels of soft/itchy that you may or may not like depending on how sensitive your skin is.
Now, think about wool from a hand knitter's perspective. When knitting, you feel the yarn all the time while you work - would you want use itchy stuff that irritates your skin? Or would you go for the soft fiber that is a delight to knit with? Hardly a difficult choice, I'd say. ;) The same goes for hand spinners. Besides, why spend time and effort knitting something from yarn that's too icky to wear once the item is finished?
Another aspect of wool that I appreciate is that it keeps you warm but 'breathes', which it has in common with other natural fibers. This is a combination I have yet to find in synthetic yarns. The few sweaters I've made from acrylic have made me all hot and sweaty, and not in a good way.
So, that's my opinion on wool and why I like to wear it. If you've never laid your hands on any soft wool then don't take my word for it; see if you can find some high quality, soft yarn (handmade, perhaps?) to feel - I think you'll be surprised!
*steps down from soapbox*