It doesn't matter if you do all the error checking in the world, or if you have the most beautiful graphics, if your site or application design isn't usable, it's not going to do well. Get input and advice on usability and user interface issues here.
Man, one more reason why I love jQuery. Thanks for sharing that!
Have you ever read the source for jQuery? It's the coolest 55K that man has ever created. And I love how downloading it is no bigger than, say, a 5in x 8in JPEG image.
I read it all the time
Still can't completely understand every design decision there, but I pickup some new insight every time. It's an awesome library
I still have had too many issues with AJAX to rely on it for a CMS. To me, the CMS should be built well enough that the page load time should not be an issue. JavaScript does add niceties, and it may work well with something like JQuery, but the CPU usage is still more, and if the Internet cuts out, or if the browser glitches, saving or re-sending data is a hassle. Form validation... I can definitely see using JS. But too much Javascript I just find too unreliable.
My CMS relies on a web browser. Even if the CSS is kind of messed up on older browsers, it's still functional, because no matter how it looks, the boxes appear and work.
Maybe it's just because of performance, but I don't like AJAX, and I don't think it has much of a place in a CMS, although I may use some basic JS for menus later on, and I may use AJAX for form validation of some sort. I HATE the kind of JS that Facebook uses.
Also, I only do this part time, so I don't really have the time to write both an AJAX version and a non-AJAX version that does the same thing.
I would definitely start with a non-ajax version. You can always upgrade it later using unobtrusive javascript, improving user experience for javascript enabled browsers but not braking functionality for the rest.