I use the Enhanced Comment Area plugin and have a problem with the links.
If the link is a complete address, the display in the the preview area is correct, but it is not if the address is relative
[url=http://www.mysite.com/myblog/entry.html] => OK
[url=/myblog/entry.html] => not OK
But the result is always correct when the comment is posted.
PS: by the way, it the quotes and lists were supported, it would be very pleasant!