I am going to be using my Kuhmo V70A at Cadwell on Thursday, where it is meant to be crisp and dry. I gather in the dry, a semi slick will still outperform a road tyre. I still won't be pushing it though!
Did a day of coaching in an Elise at Silverstone last winter and it was -6C when we started. Couldn't believe how much grip we were soon getting from A048s.
Last trackday was a very icy Brands. AD08's on my car didn't work. A friends didn't work on slicks. Another friend who had the most success, used a soft compound wet tyre.
I had great fun at Cadwell December 2011, once they'd spent a couple of hours gritting the track to get the ice off. Sure it was slippery, but that just made it more fun playing with the limits!