The delete post button is almost as useful as post editing.
Here is a table of Pros and Cons of a delete-post button.
Pros
Being able to remove things you shouldn't have posted
The third chance, first is wanting to post, second is rereading your post before you hit the post button.
Con
Deleted posts can make topics confusing ad not make sense.
At some forums such as inside3d, they have made solution to this, if someone has made a reply to your post, you can't delete it.
I know my post count would be cut in half at least, of there was a delete post button.
Thank you.