Show ALL comments, without refresh

I’m new to WordPress, and blogging in general, but have a query that a couple of days of searching the net hasn’t resolved.

I would like to be able to ‘dynamically’ update the comments on a blog without having to refresh the page. I have seen this done successfuly when posting a comment (e.g. using Disqus, and a few other plugins), but that only works for the comment you yourself post.

I would like ALL comments that are posted (from anyone, anywhere) to appear on the blog without resorting to a refresh. Something like Shoutcast is a good example, but this is only for chatting away from the main blog.

Should I be looking at maybe an instant RSS feed back onto the Blog page, or is there an AJAX powere plug-in I haven’t discovered yet.

Why do I want this? Well, the blog I’m looking to create may have several hundred, often lengthy, comments per article per day day, and with all the refreshing going on, the bandwidth usage will be quite high.

With some kind of dynamic system, bandwidth issues disappear, plus I hope it will make for a better blogging experience for those commenting.

Does this make sense, or have I explained it poorly?

Thanks for looking.

Mike