I got a new saddle this summer. Bliss (or very nearly)! The only problem was that I spent the whole summer and fall with knee pain every time I rode more than a mile. I rode through it, but I suspect I've done some damage by doing that.

Fast forward to December. I'd asked DBF to show me how to adjust the limit screws on the front derailleur,but it wound up being easier with me on the trainer and shifting like normal. He took one look at me and said "Dear Lord! You've been riding like that all summer?!" and ordered me out of the saddle.
Turns out that I hadn't taken into account the fact that my new saddle (the Jett) is a lot thinner than my old Selle Italia. He raised the seatpost a full inch. And guess what? No more knee pain!