I saw a funny result today, ranked 4th out of 1.2 million.
The site ranked 4th had copied the google results page and reprinted it with real links minus the google logo. It had no markup, not even a title, and the url was an ip address. google listed it simply as /home instead of giving it a better title.
It really seems like you'd better get everything right or don't do it at all. having no descriptions is better than having duplicate descriptions etc. I thought it was a classic anyway.