This offer is set to expire at midnight eastern (it's 930 now) and the results have been very pleasing indeed. We have gotten 4.7 new subscribers for every one person who opened this email, and have almost doubled his list (it was a small list).
In the future I think I can make it pull even stronger if I spend more time on the copy for the products we are going to be giving away. This is what I will focus on the next time I send it out.