In my experience, UltraEdit is one of the most, if not the most, powerful text editing programs on Windows or Mac. It was introduced to my while working my current gig and I have to say it’s pretty insane what the thing canhas a multi-row tabbed interface, script browser, macros, XML manager (to help you navigate XML files), give you a function list when working with source code, code syntax highlighting and more. The one thing that may get to you is that the UI is rather cluttered; but that can be hard to believe the UltraEdit only costs $59.95 for either Windows or Mac because of all the features that it offers its users.
So, if you want to get some real work done on a Windows machine, these are the tools that you need to do it. If you want to get a lot of editing done for no price at all, I can’t suggest NotePad++ enough. But, in my experience, if you want a “professional grade” app for editing, UltraEdit may be the way to go. Either way, you are going to be using one of the best text editing apps that Windows has to offer.