I went Glock 19 because when God carries concealed, he carries a G19...
But on a serious note, my thought is that if you can master the Glock trigger, you can master anything (I thought about the DA/SA P2000 for the same argument, but I struggle more with the G19 trigger than DA/SA guns)
Overall I think it will help you grow the most as a shooter, and the 19 is so ubiquitous and offers so many benefits that it's a great platform to know.
warpedcamshaft is right, though...chicks dig Berettas (almost as much as they dig holster wear).