Originally Posted by NWS Alpine

Most run BB30 because there are plenty of good BB30 cranks. The best for stiffness to weight is the Cannondale Hollowgram SiSl2 cranks (many people run them on non Cannondale bikes too). There are a few that have some issues like the FSA gossamer does loosen up a little but not on all of them. More often than not the source of the creak is NOT the BB30 system it just always sounds like it comes from that area as the sound resonates. Usually it's a skewer too loose, seatpost not fully greased, pedals not greased enough, headset not pre-loaded, etc. If it is your bearings it's very easy to apply some Loctite green which is gapping compound and it will keep the bearings seated and resolve any issues.

If you do want to go with a Shimano crank that is fine but you add a lot of weight which is one of the benefits of going BB30. Praxis Works has a very good solution and I would not use anything else if I was going with Shimano cranks like the 9000. http://www.praxiscycles.com/pages/conversion