if Mike Williams is there then obviously him.. I love the guy, he is top of my draft board by a mile. He is awesome, and I honestly don't think that there is a player in the draft that can influence this team as much as he can.
However, I can't see him getting to #7, consequently, although I'd want a RB, I voted for Antrel Rolle. He is a big, fast, physical corner that is in the Saban mold because of his mature muscular frame and long arms. He can be a genuine difference maker, and over the course of two seasons Madison/Surtain becomes Rolle/Poole and we have our CBs sorted for the next 8 years.
Rolle has been compared very closely to Chris McAllister, and his only knock has been speed, but 4.49 is very fast.