Nginx is great, but before you get down and start using it, make certain that you'll never, ever use any features it doesn't support. I was bitten by this when I found out Nginx has no equivalent to Apache's mpm_itk_module.
I mean, I understand why Apache needs to do it: with Apache, you have things like mod_php running in-process, so it makes sense to restrict Apache, running one of Bob's scripts, from accessing Alice's files.
But with Nginx, anything with "intelligence" runs out-of-process. What Nginx expects you to do is to run it as one user, but run each app server (in PHP terms, each FCGI socket daemon) as the user whose files that server should access. (Or, better yet, run the app server in an LXC container along with a bind mount to only the files it needs to access. Very Plan9y.)