I still love NFS. It's a cornerstone to how I end up thinking about many problems. In my house it provides a simple NAS mount. In certain development environments, I use sshmount because of it.

But I really loved the lesser known RFS. Yes it wasn't as robust, or as elegent.. but there's nothing quite like mounting someone else's sound card and blaring music out of it, in order to drive a prank. Sigh...