Just doing a bit of research on google caffeine and came across this tool which I thought others might be interested in too. Just type in your keyphrase and see your SERP on old google search and google caffeine side by side.
There doesn't seem to be a great deal of difference which is good!
Yes, there's a bit of movement, but it doesn't seem to be giving back results that are hugely different. (Sorry to hear about you losing a few first page rankings - that's tough.) I guess it will take a while to work out the exact differences and what needs changing in our approach to SEO.