Share 'What kind of file server are you using?'

What kind of file server are you using in your office? Currently we use WebDAV (on Apache) and samba to share files from a single server in our office (with backup.) WebDAV and samba are easy and cheap to build on a linux/unix environment. Now we are looking for a more sophisticated storage solution. I wonder what other people use for file servers and what the trend is now. Does anyone know which…