The R1200S looks like its going to be alot of fun. Its the same boxer motor that's in my RT but the S is almost 100lbs lighter. It is misunderstood by the inline four crowd but boxer is way fun. Pretty torquey low down but can really scream at the higher revs. The two cyclinder is kind of shakey and untamed but gets smoother over time, most BMW riders don't consider the boxers completely broken in until 10,000 miles or more.
http://www.bmwmotorcycles.com/bikes/bike.jsp?b=r1200s