This becomes especially useful with Hardy, which gives unrecognizable names to the unnamed partitions like "100 GB media" etc.

I think Ubuntu needs a proper, pretty, functional, simple and friendly Graphical Interface to format Pen Drives and other Hot Plug devices. Because gParted and others do it really good but are generics, a lay person new on Linux or a lay person newly arrived from Windows™ can do serious data loss if he/she choose the wrong device on the partition table for example. And it only format, don't have any special feature to Pen Drives and other Hot Plugs. A Specific GUI (Graphical User Interface) only to Pen Drives and other Hot Plugs like Cellphones and MP3™ players would be so a great feature and help. With unique features like pass and covert videos - using existing codecs like mencode - to MP4™ players for example.
I think it is easy, just create some Glade, Gambas2 or Gazpacho + GTK, cause the features are already there, ready to become together. Like i said, a GUI that links directly to USB or Bluetooth on the System and identify only these devices, use already existing codecs, and already existing functions/commands like mkfs, lsusb and othes, and pop up it all friendly to the user, to let he/she choose safely what he/she want to do.

Edit: +add christopher_lees suggestion - "Right-click on the device and choose "Format Drive...", give it a name, give it a filesystem, and click Format. An absolute necessity."
kernel_script - Just add a gksu on that action and would be perfect.

Examples:

=Hot Plug Devices Config= (HPDC)

"That tool allow you to easy manage all your Hot Plug Devices like Pen Drives, Cellphones, MP3™ players, MP4™ players, Bluetooth Cellphones and others. You can easily and safely format these devices, convert you favorite videos and music for you MP3™ and MP4™ players, and, rip your CDs direct to these Devices"

And some example of tools that could be used:

mencoder, ffmpeg, some code fork from SoundConverter and Sound Juicer, or ,just click on the option on HPDC and call them, mount and umount options specifically for these devices and format options for these specific devices. (like just put some direct paths like mount or umount /media/sda etc)

[....]

Currently there is no way to easily share files between multiple local users. I am talking about full read-write access to particular folder, eg. music folder.

Example: Alice and Bob uses the same computer. Alice has read access to Bob's home folder. Bob has read access to Alice's home folder. They want to fully share (read/write) their music. So they should ideally create /home/music folder, put all the music there and use it. Everything Bob puts into there, Alice should be able to read and remove, and vice versa. This is currently impossible in Ubuntu. Bob has to manually fix permissions every time Alice wants to delete something Bob's (Bob creates /home/music/Britney, but Alice can't delete /home/music/Britney/song1.mp3).

I have discussed this issue with several linux gurus and there is currently no easy nor difficult way to achieve this in Linux on the same (ext3) partition. With every proposed solution I can give you counterexample (group permissions, ACLs, local Samba, local NFS, etc - there is always problem when moving files). There would have to be created utility to set shared folders and some daemon would have to monitor changes and modify permissions.

Currently the easiest solution known for me is to share files on separate (ironically) NTFS partition, because when mounting NTFS you can force user/group/permissions on file access. What a shame, we use Microsoft technologies just to share files between Ubuntu users.

This problem is quite serious, give it a thought or two. Everyone who is not using Ubuntu computer alone and wants to share music/films/etc between multiple users knows what I am talking about.

//New info:
Atany has proposed in the comment that BindFS project can be used to achieve this functinality:
http://code.google.com/p/bindfs/
I have tried it and it works very well. Developers which would like to implement this idea should have a look on BindFS, it's very promising tool, it could provide all necessary background for this.

I've observed in my job that most of the users forgets to empty their trashes regularly, and suddenly one day they start to have problems due space limitations, or they don't know where is used their hard drive space.

When I click on something to drag and drop (drag-n-drop) it e.g. in Nautilus, the window gains focus and is raised. If the destination of my drag (e.g. another nautilus window) is above the window it is lowered and obscured. This forces me to arrange my windows before starting a drag and drop so that my destination is still visible when the source window is raised. This could be fixed by windows not being raised until mouse release instead of mouse down. Ideally, though, there would be a special case where if drag and drop is initialized the window isn't raised until release, otherwise it is raised on click.

The gnome-panel, an application which I really like because its ability to be customized and functionality, is sometimes painful to organize. And I say painful because when you want to move an item, or remove one, you have to unlock, move and maybe lock again, every item.

When I start the Ubuntu LiveCD and my keyboard or mouse isn't detected that is very annoying. We cannot expect people to know shortcut keys to start a mouse, or how to turn the on-screen keyboard on.

I'd like to see a right-click-and-drag option: you right-click an icon, and after dragging and releasing out pops a context menu with 'create link here', 'move here' and 'copy here'. It's very useful, and one of the few things I like about Windows XP that Ubuntu doesn't have.

I'm an artist and I'd really like to help with some of the Ubuntu art projects, problem is I had to visit around 3 different sites clicking on some 8 different links to get there and then I had to subscribe to a mailing list

When closing a window, it is currently not obvious for the user to know if the app is still running in systray or not.