Suggestion 1:
Instead of users having to use [highlight=vb.net] I think vb.net should have it's own tag, just [vb.net].

Suggestion 2:
Make a "Select All Code" button that will auto-highlight the contents of a [code](/code) block (or other code-type blocks)

Suggestion 3:
Whenever I copy code from a post that used [highlight=vb.net] and paste it into my program, it always has # signs in between each line. Is there any way to make it not do this? I think it would be more beneficial to just take out the numbers, they are helpful but they do more bad than good.