Apple just fixed everything that was wrong with Apple.
Last year's WWDC keynote left me disappointed and appalled. iOS 7 was ugly. None of the new features were that great. Even AirDrop was gimped by making it only work between iOS devices. Nothing came together in the way the Apple products usually do. But this year, it all fits together.
They have some great stuff for making iOS and OS X work together, like that AirDrop can finally work between my MacBook and iPhone. iOS 8 finally allows apps to talk to each other. (Fingers crossed that support for setting a 3rd party browser as a default will come with that.) 10.10's new Photos app looks amazing. You can answer calls and send SMS messages from any of your Apple devices. 3rd party keyboards are finally supported on iOS. 3rd party apps can now plug themselves into the share sheet. Spotlight got so much better on both platforms. Siri gained some great functionality as well. Instant Hotspot is even a great little feature that so many people will love. Oh and Touch ID is finally useful!
I'm also incredibly excited about the possibilities that Swift and Metal just opened up for new apps and games.
Only thing I'm not thrilled about is that I just sold my iPhone and just bought a Galaxy Tab 10.1. :(