Since I'm a college student, I'm apt to take notes on my laptop in class. A pile of sticky notes won't work so great for this though. I found and installed Tomboy when I was using Dapper, and it was useful. It was included by default in Edgy, so that was great, and now in Feisty, there have been 2 very neat improvements made.
First, there are now bullets. Yay! The bulleted lists indent themselves properly without leaving second-lines starting at the far left. I always fought with the old Tomboy to try to use outline form on my notes, so this is a great help. To insert a bullet without using the menu, type an asterisk (*), a space, and what goes next to the bullet. When you hit enter, it'll turn into a bullet and re-align. You can indent and un-indent using tab and shift-tab respectively.
Second, it now works like a wiki! In the preferences, enable the "Highlight WikiWords" option. If you type a word using WikiStyleCaps, it will highlight that word, telling you that it is ready to make a new note for it. Click on it, and a new Tomboy note opens up with that WikiWord as the title. If you don't want to use WikiStyleCaps, you can also type a term, highlight it, and click the "Link" button at the top. This will turn the highlighted word into a link to another note with that term as the title. I didn't think it would allow spaces, which is why the screenshot has an underscore, but I just tried it out, and yes, spaces are allowed. In my opinion, wikis are a great way to organize your notes for quick reference when studying. You can also see what other notes reference the one on which you are working by clicking Tools > "What links here?"
Of course, the old features, like exporting to HTML, highlighting, searching through notes, and importing your sticky notes are still there. More features can be added via plug-ins in ~/.tomboy/Plugins for more functionality, but I'm just pointing out the "default" ones.
By the way, you don't have to be a Linux user to try Tomboy. It has been ported to Win32, though not everything works exactly as it should.