We use the following forums on a regular basis. Forums in bold are staff favorites.

      AVS Forum - One of the largest and most complete covering the entire home audio and video market.
      High-Def Digest Forums - The name pretty much says it all.
      Home Theater Forum - More casual than a lot of the other forums.
      Home Theater Spot - Vendor based with a ton of Mitsubishi rear projection owners.

      Roku - Everything Roku.
      Rotten Tomatoes - Over 5,000,000 posts and counting.
      Slim Devices Community Forums - Everything Slim Devices.
      Sonos - Everything Sonos.
      TheaterTek - The best HTPC software DVD player.