Suprised no ones mentioned solareclipse.
Although it doesn't do code completion, which is what I really miss, and the syntax highlighting is a bit hit and miss, its what I use at work, and the best we've found so far.
http://solareclipse.sourceforge.net/ I would consider paying $30 for MyEclipse if it did code completion on JSPs, just had a quick look at their website and couldn't see if would or not.
Think we tried colorer, but decided solareclipse was better (seem to remember that colorer doesn't let you use spaces instead of tabs, amongst other things).
Ideally I'd like an HTML/JavaScript/JSP editor that worked in the same way as the main
Java editor for Eclipse, and provided code completion for HTML and JavaScript which I always end up having to reach for manuals for when I'm forced to work on JSPs, and for free - but suppose thats asking too much - be interesting to see how the various plugins develop over time.