It depends. If you're interested in high level tech and start-ups, then SyncNorwich is the way to go. If you like lower level stuff like coding, then Norfolk Developers is your best bet. If you're into game programming then there's the Indie Game Developers. For local business in the digital arena there's Hot Source.
But the thing is, they all compliment each other really well and to get the most out of tech in Norwich you should attend them all as often as possible, I do.
If I had to choose then it would be Norfolk Developers, but of course I'm biased, so it's important to make your own mind up.
Why don't you try theSyncNorwich lunch tomorrow.
