4. Tony Romo

The Cowboys had sought a franchise quarterback since Troy Aikman's retirement, and they found undrafted gold in Tony Romo, the starter since 2006. The free-agent rookie at first struggled to stay on the roster but blossomed into a two-time Pro Bowl selection. He holds single-season team records for TD passes (36), completions (335), yardage (4,211) and 300-yard games (seven). (Matt Slocum/AP)