I use tablet instead of mouse. Why? It feels more natural when compared to mouse especially after you get used to it. And freehand drawing in Gimp becomes much easier and gives better results when you replace you mouse with tablet device. The only tablet manufacturer with good Linux support (provided by the community) is Wacom. Linux Wacom driver consists of kernel module and Xorg driver. Latest Wacom kernel module and Wacom Xorg driver can be found at Linux Wacom project Sourceforge site. It is very important for me to have my tablet in top shape on my Linux PCs so I often grab latest driver from projects Git repository and go trough process of compiling it. You might have some brand new Wacom tablet without support in your current Ubuntu distribution so you should do the same. Problem is that Git repository can sometimes be in semiusefull state because, after all it is the place where development is taking place.