I was just logging in to get my bill amount and check in on things and noticed they revamped the site a bit recently. They can now display daily usage per day and when even down to the hour if you pull up a certain day. Exportable and semi-useful graphs are in there.
I posted up here ages ago about how bit all your bills were and how you were doing it (I seemed to be paying a lot for power in the past). We've split our bills in half by making some pretty tiny changes. Anyways, thought I'd mention it because I always like digging these types of stats up.