My question is, if, in this day and age, we should be required to cater for users that don't have javascript enabled?
Yes, definitely, if the AJAX functionality is core to the working of your site. If you don't, you are effectively denying users who don't have Javascript enabled access to your website, and although this is a rather small proportion (<5% I believe), it means that they won't be able to use your site at all, because the core functions are not available to them.
Of course if you're doing more trivial things with AJAX that just enhance the user experience but are not actually central to the core functionality of the site, then this probably isn't necessary.
