I was very pleased to contribute to the SANS Top 20 this year, working under the tutelage of Rohit Dhamankar, and cooperatively with Adam Safier, specifically on the P2P section.
Each year this list brings value to the global information security community, I am proud to have participated, and look forward to contributing again next year.
Bruce Schneier offers some excellent commentary on it, as well. A slightly different view can be found at SearchSecurity.
Ultimately, although I speak for myself, I am quite certain that SANS intends for this list to provide the impetus to aid enterprises in the endless challenge of tightening their security posture.
Use it in good stead! Cheers.