I'm looking for a single exe text editor, similar to Notepad.
I don't need any fancy features, as long as it's a single exe file that doesn't need to be installed and can run from the desktop or a flash drive.
I think one of the most powerful text editors out there is Notepad++, which also has a portable version.
Also, there's EditPad Lite, which has a portable installation option.
I've used both, but generally I definitely prefer Notepad++ because it's very feature rich.
I use this all the time, "Win32Pad" http://www.gena01.com/win32pad/ .
I have not used this, but if I were to give up on Win32Pad (never!), then I would look into this one, "Metapad" http://liquidninja.com/metapad/ .