I would think an editor under an emulator would drive me crazy -- it always adds a bit of lag to interactions. I really like TextMate, and I've used it for a wide range of development editing tasks. I'm not really a power user of editors, so I can't speak to the fancier features, but one thing I do like is how it has a project drawer that lists all the files you are working with, or that are in the parent folder, or however.