You'll find quite a load of positive feedback on the Conti DWS
- one of the key areas of improvement was road noise (it replaced the old extreme contact - which got very loud as it wore)
I've put these on a few friends cars and everything from 745il's to Mini's and had very positive feedback from everyone.
If you need one tire for the best possible year round performance this is probably it.
A couple others to note though,
Cooper Zeon rs3-a
and Pirelli has a new tire called the P7 that looks promising but new enough that I don't have any feedback yet
I also whole-heartedly agree with aerosaaber - you can't beat having two sets of tires!