Interesting... Everyone picked Troy Polamalu. Nothing wrong with the choice. Troy is an amazing player. You really can't go wrong with him.
BUT......
Ed Reed is a better safety. Besides the ball-hawking skills, Ed Reed is the best safety. Where do you want your safety? In the secondary, or by the line of scrimmage? Troy makes a lot of plays close to the line of scrimmage. He's more like a linebacker in that sense. Ed Reed plays the secondary like no one's business.
You can gameplan against Troy. You can actually make him completely ineffective in a game. You can't do that with Ed Reed. You can't game plan against Ed Reed. For example, Peyton Manning said Ed Reed confuses him. That's a HUGE compliment.
Troy can't cover to save his life. Think about it. every single time Pittsburgh plays New England, Green Bay (Super Bowl), or Indy, their secondary gets shredded and you never hear Polamalu's name. If you force Polamalu in coverage, he is not effective at all. Remember when Brady ripped the Steelers earlier in the season? Do you even remember a big play Troy made in the Super Bowl. The Packers made Troy Polamalu a complete non-factor. When Indy played them, I didn't see Troy making any big plays. The Steelers play a prolific QB with multiple receivers, Troy disappears...
That never happens with Ed Reed. That's why he is the best safety in the league. I don't need Reed at my line of scrimmage. That's what linebackers and D-linemen are for...
Troy is a great player, but Ed Reed is a better safety....