I use FireBug to debug my AJAX requests. It lets you examine both the contents of your request as well as the response that was sent back from the server. (it also notifies you in the console when these occur, which is a useful feature that Chrome seems to lack).
In Chrome, I only seem to be able to view the requests, not the responses. When I try to examine the response the UI Developer just displays "No Content Available" (Developer Tools > Resources > myRequest.php > Content). Do I have to turn something on to make the Chrome developer tools remember these requests?