Wow did we get off the main subject or what?
IMHO, relating to the original post...I agree with some of the posts addressing the attitude problem. Also as was stated, luck was with you in that the ladder did not hit something other than the ground and damage part of the house or worse hit someone.
I would recommend that you have a talk with all your employees about safety. Make it at least a weekly thing of relevant safety concerns, (i.e. ladder safety)and impress upon them that you are concerned for their safety as well as everyone else's. Next, if the guy was to offer to pay for the ladder, that is nice, thank him for the offer and you go and pay for the new one. One of the concerns here is: say you fire him, and when he is getting "his" tools together, he goes and picks up the ladder "he payed for," can you keep him from it??? I think not. Regardless, it is your company and things get lost, damaged, stolen or whatever. It is a cost of doing business. Claim the cost of the replacement on your taxes and move on.
In regards to his attitude, has he had a bad attitude at other times? Is this isolated? Is he worth keeping? If you honestly feel his attitude is bad and he doesn't care about his work or your business reputation, simply get rid of him. But do not fire him because of the ladder falling. Unless you have documentation of prior disregard of safety issues and written warnings, you will loose if he takes you to court or the LRB.
If you are a small company like me, I am very picky about my employees when I have them. I won't put up with either sub-standard work or bad attitudes...maybe that is why I do so much of my jobs by myself?!
It is your company, make the call!