I don't know too much about psychiatric medication, but I can tell you what I do know.

Benzos (e.g. Klonopin, Xanax, Valium) are amazing for acute stress and anxiety. Klonopin seems to be the "mildest" of those. It erases my anxiety and gets me back to normal functioning without making me feel impaired. Benzos in general act on some of the same neurotransmitters as alcohol. Stronger benzos can make you socially disinhibited, physically impaired and/or put you to sleep, just like alcohol, but I've never had that problem with Klonopin. The big disadvantage of benzos is their addictive potential. If you take them every day, you'll get addicted to them in a matter of weeks. Benzo withdrawal is supposed to be worse than alcohol withdrawal. However, if you take them intermittently (e.g. once or twice a week), they shouldn't have any adverse effects.

Another popular treatment for anxiety and PTSD are anti-depressants (SSRIs), but they don't work well for everybody. They can have unpleasant side effects (dry mouth, too much or too little sleep, loss of libido) and their positive effects don't kick in until several weeks into treatment.

Some psychiatrists like to prescribe atypical antipsychotics (e.g. Seroquel) as an alternative treatment for anxiety and PTSD, when there's concern about the addictive potential of benzos. I wouldn't recommend that though. Yes, they will immediately take away all of your anxiety, but it feels as if they'll suck the life out of you... I have met several people who were prescribed antipsychotics (for a purpose other than acute psychosis) and not a single one of them would voluntarily take it again...

There are supposed to be other non-addictive drugs for anxiety, but those above are the only ones that I have personal experience with.