I can't see why The Gimp is a standard tool to install, it's a bit specialist and not very easy to use. Paint.NET is better if you actually need something, but I doubt you do.
NotePad++ would definitely get my vote.
I'd say use MSE rather than Avast.
Surely Acrobat Reader is a requirement?
Not sure on why bother with FF and Chrome, I'd say pick one as an IE alternative personally.
AdBlock possibly makes sense but not script-blockers because it sounds like your target users will not know what's going on when pages don't work properly.