Well... I've been doing a little playing with Coda, and while I have to say it's very nice, and it's got a ton of flexibility. I think it's the tool I've been looking for to do the larger scale, faster AJAX building and deployment. You can put the CSS for a web page in the page, which is quite nice, but you can also put it in a general CSS file, and share it among many pages. Nice flexibility.
Of course, with preview is Safari (WebKit), so the JavaScript is working in the preview, and while it's not exactly like Safari because I can't set my default fonts in the preview pane, it's probably a lot more representative of the typical user than I've been thinking my Safari and Firefox sessions are. For example, in Google Chrome, by WordPress blog looks very different - primarily in the font selection. I'm not sure which is right, because Safari, Firefox and Camino are all looking the same and it's only Chrome that's odd. Maybe it's just Chrome.
Anyway, it's probably a decent thing that the preview is very generic, as it'll force the proper use of CSS. That's important for a whole host of reasons, not the least of which is that these days you have to have CSS or the page looks horrible on just about any browser.
So I was thinking that with Coda, I had a really nice tool to build the pages. But then there's the complete object-oriented development tools. The plus there is that I have the Google DataTable in Java, and JavaScript, and that serialization is done very nicely, but in general, I really need to think about building up some JSON serialization tools for things like Maps and Lists in Java. It's not a complete 1:1 mapping, but there are a few things I could write that would make it a lot easier to serialize out some standard Java datatypes to the JavaScript world, and that would make it faster to build pages.
Still... writing the Java code isn't the long pole for AJAX development for me. It's more the initial building of the HTML page based on all the ways of putting it together. All the different tags and structures are more than a little challenging on multiple browsers, but it's something I'm getting used to, and in time, I feel, it's something that will come as second nature. But for now, it's the one thing that would benefit from a builder tool.
In the end, it's still one of the most enjoyable development environments I've coded in in a while. Glad that I have the tools to do it easily.