Want to see if you doctor has been taking money from pharma for meals/consulting/speaking/etc? Look them up in ProPublica's Dollars for Docs: https://projects.propublica.org/docdollars/
I was also at the TimesOpen Hack day, and spent most of the day coding. There was a lot of chatter there, though (some of it contributed to what my app eventually became). Bring headphones for when you need to start building. Thankfully no one there presented deckware.
You get something similar to this with the bit.ly sidebar bookmarklet. When you shorten a URL, it tells you how many clicks there have been on all bit.ly-shortened links for that URL. I always check out this number, and if a link has over a certain amount of clicks, I usually won't tweet.
What new features would you want? I still use Tiger on my primary machine and haven't missed much (outside of performance boosts) in the subsequent releases.