I guess I'm on the fence on this one. I guess it's like the coyote/wolf controversy in some ways. You love 'em or you hate 'em.

On one hand, bats do eat mosquitoes and are in some cases endangered, but then they do carry rabies and could be vampires as well. It's two against two. Actually, three against three, since bats are know to fly into women's hair which creates a lot of damaged hair do's. But I have also seen a movie where a young lady, in the course of trying to free a bat from her hair, somehow managed to be liberated from her brassiere.

To summarize:

Bat Pro's -Eats bugs, endangered, possibly freeing of boobies
Bat Con's -Rabies, vampires, tangled hair do's