Personally, I would be aggrivated. I would ask him nicely to pay, or at least compensate for 1/2 (even though it sounds like he was 100% at fault. If he refused, I would let it go. If they got him all fixed up for $120, you got off good. I am not saying I would be a happy camper about it. However, the stress of dragging it out in a small claims court, would not be worth it for me. You may get your money back in the end, but will probably loose a couple more fishing trips dealing with it.

I would be he had no intention of causing harm to your dog, but should have showed a little more responsibility as a pet owner. I think, since he was taking the time to walk his dog, and wasn't too ashamed of the girly dog on a pink leash, he probably has some compassion for dogs in general, and will probably be willing to help you out, as long as you are not too confrontational.