[Agama]

I've also had a play with Sigil and it's quite impressive; a great tool for stripping out unwanted sections/pictures from free epubs, (e.g. Feedbooks), in order to minimize their size. However, I have had trouble with some calibre generated level 3 TOCs within Sigil - they simply didn't show up. The search/replace works well in Sigil but Notepad++ is exceptionally fast and has extended options for matching special characters, (e.g. linefeed, carriage return), and for matching Regular Expressions. It's a good editor for source code as it can colour code syntax for many different file types, including html and xml. There's also a handy macro record/playback facility to do repetitive edits.

I've had a look at the UltraEdit website and their editor looks like Notepad++ on steroids. Could be a good investment if you want the extra features, for example scripts look a really useful tool.