Generally speaking, I have been quite happy using Nautilus with a little help from Tracker from time to time. Nautilus is a no nonsense file manager that allows most users to get the most out of their files and the way they choose to manage them.
If something gets lost, Tracker can be used to locate the missing file very easily, as it allows "searchable" access to e-mail, images and documents so long as you have some idea of what you are looking for. And this is where this latest idea to the file manager world comes in.
Meet Nemo. Simple name, brilliant idea for tracking file changes. Not likely to catch on with the casual user, but I do suspect that Nemo will be a hit with anyone looking to revert to previous versions of select files or showing interest in improved file tracking abilities.
Treat Your Files And Documents Like Gmail.