I've noticed a lot of people giving information from the time remaining estimate that is given in the top menu bar on the computer. Have any of you actually used it until the battery ran out and kept track of the actual time it was up and running? I'm just asking because the time remaining estimate is a snapshot for that specific time interval. It changes rapidly depending on what you're doing, and often isn't very accurate. I'm just curious what people's actual usage times have been like.