For a really long road trip I love the Anakee 2. If you don't need to get 8000 miles out of a set I like the Battlewings, they aren't too bad on gravel and dirt, great in the twisties, and decent in rain. Soft rubber, I heard its the same mix as is the BT020 which was a fantastic sport touring tire. A little cheaper than the anakees and tourances as well. I only get about 5000 miles out of them tho.
And for the record I have tried every air pressure in the book and I still seem to wear the fronts out at the same time on most every tire I tried on the Beemer. Just don't know what to say about that.