Forums

General Bitcoin Discussion

• BitcoinTalk Forum (formerly located at Bitcoin.org)
• Bitcoin Subreddit
• BitcoinForums.net
• Bitcoin TweetForum
• Bitcoin-Board Forum
• BitForums.net Forum
• BitcoinMe Forum
• Bitcoin google group
• Bitcoin.in forum (SMF)

Language Specific

• Bitcoin Italian forum
• Russian bitcoin community forum

Other

• MtGox Live Traders Forum
• Bitcoin & Crypto-Currency StackExchange site (still in proposal stage)
• Developer mailing list