Lexapro has been a huge help for me with regard to panic and anxiety. It's an SSRI like zoloft, paxil, prozac, etc, but the side effect profile tends to be much milder. The only side effect I've had on it is night sweats, which is annoying, but definitely tolerable.

Since it is an SSRI, though, you can't really use it on an as needed basis like you can benzos. As far as I know, you have to take it every day for it to work.