For more relevance, I'll not consider the legends the likes of the Gipper, etc.
1. Ross Browner - The greatest player to play at Notre Dame. He was a man among boys, and for a big defensive end, had no trouble running down running backs, covering wide receivers, out-finessing offensive linemen, or flat-out overpowering them. Watch some of the videos of his play, and you'll see him casually throwing aside 285 lb offensive linemen as if they were rag dolls (back in the days where 285 lbs was considered "huge").
2. Joe Montana - Not so much for his collegiate play, and more for his professional play. He deserves accolades for his clutch performances in college, though, including the Chicken Soup Comeback against Houston.
3. Raghib "The Rocket" Ismail - While his stats weren't as eye-popping on paper, no one player ever forced opposing defenses to change their strategies as much as he did. Even if he didn't have big receiving numbers, his sheer speed and acceleration, along with his ability to spin out of tackles, would force defenses to assign both a cornerback as well as an extra safety to spy on him. This opened up the rest of the offense, since he took away another defender in the box.
4. Jerome Bettis - The big black bowling ball (that's what he called himself at times) would simply run over many a linebacker and defensive back. To see a giant running back like he was, with that much acceleration and top speed was phenomenal, and seeing him steamroll the vaunted 1991 Florida Gators' defense so easily, made me smile. Credit goes to those awesome offensive lines, but still, you could see fear in the eyes of the opposing defensive backs once he busted through the front seven.
5. Bobby Taylor - He could basically shut down the opposition's best receiver in single coverage. He ran a good 40 time (4.50 if I recall correctly), while also being 6' 3" and 210 pounds, complete with excellent hip flexibility. He also had excellent field vision. Basically, you couldn't run past him, you couldn't try to exploit a height advantage, nor a strength advantage, since he was about as complete of a package as any cornerback out there.