1) Picasa, just received a shot in the arm. Integrating it with Google+, would definitely see a surge in its adoption. Also, since people are going to use it anyways, they might seriously consider backing up all their images to Picasa. Fits right in with the Google's cloud philosophy.
2) Huddle - This is Google Talk for mobile done the right way. Given that iOS app is on the way and hopefully a Blackberry version, this can take on the new iOS messages and I dare say, the blackberry messenger.
3) Google has got the integration of notifications right, always there and yet very subtle. The top bar redesign makes sense now. With Buzz, there was a feeling of the service forced down on, in your gmail account. But, with Google+, the service notification are everywhere. web, images, books, news, g+ and yet the users do not seem to mind. Integrated the right way.
4) It has the potential to be The network. Facebook, might be a serious social network, but no is really going to use the FB email as the primary email address or as the one for formal usage. Google+ covers that. It can be your formal network; the one for friends; your primary photo service and more.
5) It would be killing, if they would Hangout a.k.a. group video chat would make its way onto the mobile apps.
This might seem positively biased, well, I do love Google.