(Replying to all the messages in one)
I guess right now I'm mainly looking for a good (to a certain extent, read: dedicated) XML editor and haven't yet encountered one for OSX. Aside form the "standard" text editor features, the two biggest things I'm looking for are automatic (via keystroke) closing element tags* and highly extensible syntax highlighting.
I've been told that jEdit performs excellently at the latter, but haven't had a chance to test it out yet. One of the big things I'm looking for is the ability to use multiple highlighting pragmas in the same file (i.e. CSS embedded in HTML, JS in HTML, PHP in HTML, XSLT in XML, HTML in XML (aka XHTML), et cetera).
Take the time to look at jEdit then, as it's pretty darn extensive, and what it might not do, there is probably a plugin or macro to do...
Pete