My first game Flotilla used XNA. After that I switched to SFML.Net, so I could go cross-platform. Switching from one to another wasn't that bad - I use my same home-brewed "engine" across all my games, I just needed to plug my low-level drawing/audio calls from one library framework to another.
To get SFML.Net running on Mac & Linux, I use Mono.
Other than that, I don't think I'm using other tech - I'm not very tech-oriented, and even if I wanted to go tech-heavy, I don't think I have the know-how!