By far, the most popular DIY project for the Raspberry Pi is to use it as a retro game console. So, with the release of the Raspberry Pi 3 a lot of people are curious how it performs in comparison to older models. Adafruit did a live stream showing just that.
Adafruit's video is just a stream with a base setup of Retropie, so some of the glitches they run into are likely things that you could troubleshoot around. Regardless, the video does a good job of showing how the emulators look and perform on the new Raspberry Pi 3. If you don't feel like watching the video, the basics are pretty straightforward: NES, Game Boy, SNES, Genesis, Gameboy Advance, Nintendo 64 and Playstation all work great. They had decent luck with some PSP games, but had some sound glitches along the way. They also had trouble with emulation on Saturn games and Dreamcast games (which could just be a control setup problem), and couldn't get Nintendo DS or Sega CD games to load at all. If you head over to YouTube, they have included time codes to jump to specific parts in the video for each console if you're curious about how one system looks.