Rajiv,
Going with latest first will break the whole concept of the thread. There is a huge difference in keeping latest threads up as compared to keeping the latest post on the top, since threads by nature have no direct co-relation to each other, while posts are very much dependent on each other.
The post by JoeF, was a great example of what would happen if the latest posts are posted first. This is a simple UI issue and you can check any of the other forums that abound the internet, the posts are always in a first in, first displayed manner. Besides the latest post is only one click away with the "last" page link. The effort is well worth keeping the logical progression of the thread intact.
A better way to deal with the problem of navigating a number of pages would be to spawn a new thread after the number of posts on the original thread cross a certain number. That way it doesn't become too tedious to read through all the prior posts.