I think Andrew Miller's going to be the #1 pick. Mid-90s fastball that can top out in the high 90s, great 2 seamer, slider that has been compared (although probably an exaggeration) to Randy Johnson's, and a projectable 6'6" 210 lefty frame. He's been ticketed to be the #1 pick in this year's draft ever since he didn't sign with Tampa in the 2003 draft (

). His command leaves a bit more to be desired, but he can pitch effectively wild at times.
Scherzer might have the best fastball in the draft, but his breaking pitch, while effective, isn't near that of Miller's. Plus, he's going to have signability issues as a Boras client (although Miller may have signability issues of his own).