I have list of PC must haves in my toolbox. A good text editor is a must. I have been using Textpad ( http://www.textpad.com ) for a long time and really have nothing bad to say about it. It can open large files and has a decent regular expression editor. It is able to delete at column and row level.
I dabbled with Notepad+ and Notepad++ as I looked for replacements for notepad. I used Editpad for quite some time.
When I attended the BuildWindows conference this summer, I saw many of the presenters using Sublime as a text editor. It runs on both PCs with Windows and Mac. It also works on Linux. It seemed to be the consensus editor of choice. http://www.sublimetext.com/. I have enabled my Sublime plugin to prettify the XML files I work with on a regular basis. I used this tip here: http://www.bergspot.com/blog/2012/05/formatting-xml-in-sublime-text-2-xmllint/
You will need the xmllint command for your PC from Google CodePlex. https://code.google.com/p/xmllint/ Take the one that allows inline piping.
More about xmllint: http://xmlsoft.org/xmllint.html
The command line to fix your XML: xmllint –format –encode utf-8