Anything that writes text is fine.
I recommend the standard text editor for your OS (Notepad if you use
Windows, Textedit on Mac, whatever is on your GNU/Linux distro by
default) unless you know exactly what you don't like about it.
No. Don't use Notepad for anything! It's easy enough to get a better
editor. Among its other faults, Notepad:
1) Has problems with LF line endings (they vanish, and you have hugely
long lines)
2) Puts three junk bytes onto the beginning of a file that it
considers saved as UTF-8
3) Doesn't understand coding cookies, and will happily save something
in a different encoding like CP-1252 (which it calls "ANSI")
4) Guesses encodings on load, giving rise to the famous "Bush hid the
facts" trick - although this is unlikely to be a problem with
something of decent size
5) Has issues with large files - or at least, it did last time I
tried; this may no longer be true with Windows 7/8
Default text editors on the Linux distros I've used have been far
better, but still less than ideal. With Debian Squeeze, I got a gedit
that bugged me in several ways, which is what pushed me onto SciTE.
You can certainly start coding with gedit, though. The issues that I
had with it were relating to heavy-duty usage that I do, where I'm
basically spending an entire day delving into code and moving stuff
around. These days, though, I'd rather have one editor on both the
platforms I use (Windows and Linux, each in multiple variants), as it
allows me to share configs and comfortable keystrokes. There are
plenty of cross-platform editors to choose from.
So, I agree with your analysis, as regards gedit ("know exactly what
you don't like about it"). If it doesn't bug you, use it. But if
Notepad doesn't bug you, *still don't use it*, because it's like
driving a car that isn't structurally sound. It might not be you that
gets hurt by it... or it might not be for quite a while that you see
the problems... but the pain will happen.
ChrisA