How much to charge in a security deposit?

[Michael DeStefano]

I've been mulling this over for a while now and I'm not sure how much is the right amount to charge in a security deposit. So I wanted to get some opinions. My gut says something like "two months the rent" but that can be a lot for people. I currently rent and I don't remember how much the deposit was, but it wasn't much. I live in Texas and from what I've been able to research it could take up to 2 months to evict someone. So my concern would be that I'd be out to months rent and then if I happen to get one of the horror stories of a tenant trashing the house out of spite and anger I'd want to be able to repair any damages. 

So my question is how much does everyone else charge? Do you have a formula based on the price? Is it the same for every property? Or do you have some trick to figuring it out? Thanks in advanced!