Non-Linux FOSS: Notepad++ Is Better Better
If anyone understands the importance of a good text editor, it's a Linux user stuck on Windows. Sure, Microsoft supplies Notepad and Wordpad, but neither really feels like the powerful sort of text editor a Linux user expects. Enter Notepad++.
Notepad++ provides features like line numbering, syntax highlighting and tabbed file editing. If those seem like ordinary features that should be included in any text editor worth its salt, well, you're right. Notepad++ is fully open source, and it is the preferred simple text editor on Windows. It's certainly not a full IDE, but all the developers I know have it installed if they use Windows. Give it a try at http://notepad-plus-plus.org.