Removable media, such as USB pendrives, can be inadvertently unplugged by inexperienced users before all data has been written, which causes file corruption. Also, such users' are unaware of "Eject" or "Safely Remove Drive".

Files downloaded by Firefox when the user clicks 'open' instead of 'save' go to /tmp, where they are deleted after a reboot or after Firefox closes. This is fine, but sometimes editable files such as documents and images get 'opened' and edited, and then saved. Most programs (apart from image viewer) will save the file exactly where it was by default. This would be hard to solve, as every app does things in its own way, but an even more serious problem is much more easily fixed.

Programs often default to saving to the last place a file was opened or saved from, which can lead to files being saved to /tmp almost by accident if another file was opened from there or saved back to it earlier. Users may not be fully aware of this. This means they might actually save new documents or other things they need to these folders without realizing it will vanish the next time they shut down their machine.

At the moment, nautilus distinguishes between capital and non-capital letters. So if I have a bunch of files called 'Loop 1', 'Loop 2' 'loop 3' and 'Loop 4', then they will be sorted by name in this order: 'loop 3', 'Loop 1', 'Loop 2', 'Loop 4'.

I don't think many people would want capitals to be treated differently to lowercase letters in file sorting... what do you think?

Capture all the new processes of nautilus on the same window using tabs.

Imagine that you open a folder from the desktop. Nautilus will start, and a window will appear.
Then, you go again to the desktop and open another folder. Nautilus will create a new window. But i think that it's better use the first window to open the second folder, but in another tab.
No multiple windows, only one that captures all the new "explorers" in this window.

Imagine you're using firefox and you are watching two differents websites. You have in your home folder a html document. If you open it, you won't open a new window of Firefox, you will open your document in a new tab of the opened Firefox window.

About the QTtabbar from Windows, you can watch this video:
http://youtu.be/-ClKWQrXs8Y?t=2m
http://www.youtube.com/watch?v=lnlVt7EpMTU

Certain situations demand a second or even a third property (such as size) sort on files after they've been sorted by one property (such as name).

Often, I would very much like a combination of sort-types. Sometimes, "alphabetic" fits me well, but I still want the new work-folder to be on top, or the "date"-sorting works well for a couple of folders, but is hell to look through to find an old folder.

I would like a bit more finesse to the sort-options to fit my needs better.

I'd love to be able to use single click, but I see no way to select multiple files...

When i right click a file of folder and select properties,The
properties window takes a lot of space,
The properties window doesn't let me resize them, this is the smallest you can get them http://i.stack.imgur.com/EYQTp.png. As you can see the properties window doesn't take full advantage of the space it bin given

I was thinking about a way to make Nautilus automaticlly unmount a USB-drive after a copy finished

I have lot of movies, music, etc. files inside their corresponding directories, which names and sizes (for instance) I would like to export, in order to share them with my friends.

The thing is to allow a simple way to export this data in a few clicks using the UI. I like the shell but shell is not for all human beings. Just a simple example of usability. Try to explain to your not techie father, by phone, how to send you a list of the files inside of a directory by mail.