Could somebody please detail for me a system using which one can output video to a TV from an HTC Thunderbolt? It has no HDMI port so I'll (almost) certainly need an adapter, I know. I don't really need HD quality but at least 720p would be nice.
The Thunderbolt has DLNA, so if your TV supports DLNA you can use that. On my Samsung phone, you use the AllShare app for DLNA, but I think the Thunderbolt has another app built in. Page 275 of the User Manual describes how to use DLNA. This droidforums thread has a discussion of ways to use DLNA without a compliant TV, I'm not sure how well other ways will work.
There's also a "multimedia dock" that is supposed to be released shortly, it's "out of stock" until then. That should provide a cable-based way of video output.
If your TV doesn't support DLNA and you have some other DLNA capable device, like an Xbox360, PS3, or DLNA capable blu-ray player, you can use that as a bridge between your TV and the phone.
Just set your phone to use wi-fi and run whatever app comes w/ the phone (or download some other app on the market) to stream via DLNA. Your DLNA capable device should detect the media server from your phone. Once that happens, you should be able to stream from your phone to the capable device, which would then display to your TV.
Check out these posts on Droid forum for more specific info.