For a text editor that support XML copy/paste to clipboard, try out SciTE:
http://www.scintilla.org/SciTE.html
Edit: a really useful feature, is to have things organized as “sessions”. Opening a session will make SciTE recall a previously saved collection of “snippets”. I currently have a library of triplets, that I use over and over again…their name is all I need to know, e.g. “triplet 0.25x”
