Nothing wrong with nfs but for quick & simple sharing on a lan it is hard to beat ssh. Just install the packages openssh-server and sshfs on the system or systems with files you want to share. No other configuration is necessary but you can use regular file permissions to restrict access as you like. Then from the gnome desktop you can just use Main Menu/Places/Connect to Server, select SSH for the server type, and enter the server name or ip address of the system with ssh-server running. your username if it is different on that system, and click connect. You will be prompted for a password and after that you'll get a folder on your desktop.
The sshfs package allows you to set up a mountpoint for the remote system and mount it similar to how you would mount a partition or filesystem on your local machine. Then you can use any file browser or command line tools to access files on the remote just as if they were on your local system.