I considered the Diesel, but couldn't get Carbon Black or M-Sport. That made the choice a little easier. If you are looking for 24mpg you should look at the D. But I gotta tell you, I drove one for a weekend and never got a giant grin on my face like I did after 5 minutes in my 50i.
2013 Carbon Black X5 50i M-Sport
2010 Alpine White 135i M-Sport
2010 R1200GS Adventure 30th Anniversary Edition
2010 Carbon Black M5
2007 Graphite K1200GT
2003.5 M3 Cabrio
1997 M3 sedan