Note: While the last "balance" is the accurate number of bitcoins available to this address, it is likely not the balance available to this person. Every time a transaction is sent, some bitcoins are usually sent back to yourself at a new address (not included in the Bitcoin UI), which makes the balance of a single address misleading. See the wiki for more info on transactions.

8c3d4c1ddd... Block 171155 (2012-03-14 17:45:50) 18.4995 Received: Address 18.4995
05285c4341... Block 174196 (2012-04-04 00:20:32) 18.4995 Sent: Address 0