Mame With A Title Snapshot
Now that Mame has a nice user interface, you can add snapshots to show the system you've highlighted running. You can also add dat files which contain cheats or additional information about systems.
These extra files can be downloaded from Progetto-Snaps or as a torrent from Pleasuredome. As you can see from the menu, there are a lot of different types of media files available. For the manuals, you will need to have a PDF viewer installed.
There are several other additional media files that are supported by MameUI and various other frontends. MameUI and many frontends also support folder ini files which are used to filter down the vast list of systems supported by Mame.