I came in about 45 min late to the keynote and had it on in the background (thanks to my Chromecast

) so fairly certain I missed much of the specific detail but here are my initial thoughts on what I saw/read, FWIW.
Android L
- Like some of the features/functionality I saw, specifically the lock screen notifications, and the Personal Unlocking. I believe I also read something about an Android equivalent to iOS's on screen banner notifications but haven't seen any screen shots--is it similar to iOS? These are two elements of iOS's notifications that I like and really round out the Android experience.
- Not a big fan of the new Material Design UI, at least the very little bit that I've seen so far. Seems like an awful lot of wasted space, sort of like they took the same amount of space and used smaller font/graphics--best example was the comparison of old and new gmail. I like the layering elements but the rest just doesn't seem as polished in appearance. I also really dislike the geometric shapes for onscreen buttons. Of course, will certainly reserve judgement until after some hands on time.
Android Wear seems really slick--a great job building on what existing smartphones are capable off and taking it to a new level. I question some of the functionality (i.e. not going to use my watch to complete a recipe, especially when I would likely have a much larger screen immediately available), but overall seems really cool. I haven't seen any mention of compatibility--does it work with all Android devices (I'm looking at you Samsung)? Minimum OS level required on your phone? Compatible with iOS?
Android TV seems to be more of the same--Android's take on what's already out there on other platforms. I like the functionality I saw but have reservations on how it'll actually be implemented by OEMs. Are we going to see a dozen different skins atop Android TV as we do now on tablets/phones?
Android Car also seems really slick but really need to see how car manufactures actually implement it before forming any concrete opinions.
A lot of potentially great stuff announced today. I'm containing any excitement I have though due to the fact that OEM's may very well butcher the hell out of everything.