Im not sure if this has been mentioned already as I've not been around for a while. When I post to an existing thread it doesn't seem to show up in 'new posts'. Is anyone else having this problem.
Yes, that is the the way that vBulletin Forum script works - it will disappear from the "New Post" list until another post is made, and as soon as you have re-viewed the thread it will disappear again.
To see all posts today, read or otherwise, you can use "Todays Posts" and to see all your subscribed threads simply click on "User CP"