So, in the end, when looking at all of the Cowboys to wear number 19, my choice for the best ever is Miles Austin.
Miles Austin joined the Dallas Cowboys as an undrafted free agent out of Monmouth University in 2006. He primarily returned kicks as a rookie, and he had one extremely long kick return of 93 yards for a touchdown in the playoffs against the Seattle Seahawks following the 2006 NFL season. (Granted, when he was a rookie he was wearing number 14 instead of number 19).
The following season, 2007, saw Austin step up his receiving a bit, as he was targeted 10 times and caught the ball 5 times in the regular season, now wearing number 19.
Austin would be target 23 times the following season, when he also scored 3 receiving touchdowns. It was 2009 however that saw Austin have his breakout season. He totalled a very impressive 1,320 receiving yards on 81 receptions to go along with 11 touchdowns in his best year in the league. He also had 11 receptions for 116 yards and a TD in the two playoff games he played that season. Needless to say he was a Pro Bowl selection that year.
He would also be a Pro Bowl selection the following year, 2010, when he once again surpassed 1,000 yards receiving and hauled in 7 TD passes. Although he would have some further success with Dallas, 2009 and 2010 would be his two best seasons.
In total, through eight years with the Cowboys, Austin caught for 4,481 yards and 34 TDs in the regular season.