Question: What is the earliest block in the blockchain that has a spent coinbase? I have manually looked at the first dozen or so but they are all unspent.

Answer: 
The first transaction, [Satoshi sending 10 BTC to Hal Finney](https://bitcointalk.org/index.php?topic=155054.0), was recorded in [block 170](https://blockchain.info/block-index/171/00000000d1145790a8694403d4063f323d499e655c83426834d4ce2f8dd4a2ee).
As Dust noted above, it does appear that 10 coins that were generated in Block 9, were sent to someone in [Block 170](http://blockexplorer.com/address/12cbQLTFMXRnSzktFkuoG3eHoMeFtpTu3S), transaction [f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16](http://blockexplorer.com/tx/f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16#i172) and which if what Hal says is true (I have no reason to believe its not) then Hal's address is [1Q2TWHE3GMdB6BZKafqwxXtWAWgFt5Jvm3](http://blockexplorer.com/address/1Q2TWHE3GMdB6BZKafqwxXtWAWgFt5Jvm3) and he didn't spend/move them again until 16 Nov 2010, which would coincide with the his comings and goings on the bitcoin scene.