For those of you obliged to learn the arcane ways of LaTeX I would like to highlight the logically named LateX editor (LEd). I had been using the admirable (if not so helpfully named) TeXnicCenter but a new install prompted me to look around at alternatives. LEd is a rather new one: version 0.46 beta was released on 28 April 2006.
LEd features command completion with pop-up syntax help, code folding, built-in preview, UK spellchecking, multiple clipboards and probably a bunch of other stuff I haven’t yet discovered. It doesn’t compile straight from the install but shouldn’t be too hard to configure with MiKTeX.