But if you're searching for a simple, fast loading text editor then Mousepad is pretty decent app. It's actually based on another text editor called Leafpad (which is the LXDE desktop's text editor) but again it's even more simplified than the Leafpad it self, personally I prefer Leafpad over Mousepad.
*. Although slightly slower than the Leafpad but loads faster than Gedit for instance.
*. Save text files in different formats.
*. Print preview.
*. Change font/size.
*. Find and replace text.
*. Show/Hide line numbers.
*. Auto indent.
It doesn't even has an "options" window which usually lets you configure few things such as tool-bars or customize other features but it certainly is not a game changer :). But if you're a serious writer then this is not something that I think you'd be quite happy with either.
You can install Mousepad in Ubuntu 11.04 Natty Narwhal, 10.10 and 10.04 by using the below command in your Terminal window.
sudo apt-get install mousepad
That should do it.