I have been using Notepad2 on Windows XP for a long time now. What I really like about it is that it's fast, has lots of features, and pressing Ctrl+L runs the script immediately. The entire program consists of two files : Notepad2.ini and Notepad2.exe (total size: 775 KB).
On Linux, Notepad2 is slow and glitchy with wine, so I use other things like Mousepad or Geany or whatever comes preinstalled with the distro. My three favorite distros are Slitaz, Lubuntu, and Slackware.
At one point, I decided to write my own perl editor in HTML and JavaScript (it's a HTA application in Windows), but I didn't know how to add syntax highlighting while the text is being edited. When the text is displayed (readonly), it's easy to add syntax highlighting, but when it's in a textarea box, and the user can edit things, it gets complicated. I don't know how to do that. Without the syntax highlighting, it's no good. Then the other downside of HTA app is that it will only work in Windows or in a web browser, so it's quite limited.