If you don't specify --coinbase-addr, bitcoind will try to use the old getwork protocol instead of GBT. You'll find that the daemon has a hard time keeping up with more than 10GH or so with getwork, and will be utterly useless once it pegs your CPU. FWIW if you can solve a block on getwork, the reward will go to one of the unused reserve addresses in your wallet. The reward for each block found would go to a different "random" address in your wallet.
Also - You can try out your config on testnet by adding testnet=1 in your bitcoin.conf file...
Thanks for the response. I've been wondering about a setting up a bitcoin-qt node and allowing some friends to connect using my bfgminer as the proxy rather than each of them having to run a node themselves. Then came the question about who gets the block reward when it's found.