What has been anyone's experience using effects pedals for acoustic guitars? I play with a praise band in church and do some solo gigs and would like to add a few new things to the shows.

It seems to me that it really isn't worth it buying a "specialty" pedal like Boss' AC-50 for acoustic effects. I know it says that the pedal is specially tailored to an acoustic, but I really think that general effects (especially analog ones) sound so much more powerful and carry a much greater, well, effect. I've found the same thing with effects that say they're tailored for bass. I usually use analog effects when I can.

If you're looking around for some good effects, I highly recommend:
Electro-Harmonix
Moog
Line6
Tech 21
MXR
(and in some cases) Dunlop

There are plenty other recommendations I could make if I knew what specific effect you were looking for (like an MXR Phase 90), or if you happened to be after a multi-effect pedal (like Boss' GT-3, GT-6, GT-8, and GT-10)