First of all, I am always one that says pure stats don't tell the whole story of what a catcher provides (either positive or negative) for their club.  But, I just heard some interesting stats from John DeWan (sp) that I had to share:

Barrett catching with Cubs:
record: 24-28
ERA: 4.17

Without Barrett catching:
record: 16-4
ERA:3.71

Barrett Catching for Padres:
record: 3-10
ERA: 4.10

Bard Catching for Padres:
record: 33-19
ERA: 2.55

Pretty interesting stuff.