I personally wouldn't mind Roy Keane, Man Utd association aside, the guys played at the highest level. Could possibly attract better calibre players and would turf out the duffers.
He has gained a promotion before, and played under 2 of the greatest British managers, of all time.
Leroy Lita anyone?

He's also a vile little man who fell out with his players and chairman at Ipswich which ultimately led to his sacking....