I recently got the newly released Windows Phone 7 (the Samsung Focus). So far, I love it! This is my first smart-phone. It’s nice to join the 21st century.
I’m also poking around with how to write apps for it. It was easy to download C# Express and WP7 tools and get started with the emulator.
WP7 user apps are written in WPF (or XNA). I never really needed WPF when writing debugging stacks, so I’m feeling the pain from the learning curve here.