I was reading Jakob Nielsen alert box, yesterday and found this interesting article on the top 10 User Interface design mistakes.
One of the 'bonus mistakes' that some designers do is use reset buttons on web forms. I must reluctantly admit I am one of those designers. On my last project I created a form reset. Thinking back now the only reason I wanted such a function was to make it easier for testing. It a mistake that I wont make again.
Another item mentioned by Jakob is that scrollbars seem to be the most often changed elements, and I tend to agree with him on that one, there is just no reason to change them but I keep seeing it done.
Its and interesting read, I would recommend it.
[Article can be found here:]
http://www.useit.com/alertbox/application-mistakes.html