Cornerbacks are key to covering another teams best wide receivers as well as supporting the run by keeping things inside.
NFL teams nowadays are looking for taller corners (at least 6'1'') with that combination of size, speed, strength and explosiveness.
A good NFL cornerback will also have to have jumping ability, fluid hips, good footwork in a back pedal, be physical, quick change of direction, good hands and great awareness. They also need to be able to be good in man and zone coverages. The ability to blitz effectively coming of the edge is also useful.
Here are my Top 10 Cornerbacks for the 2011 NFL Draft.