Tomsky was a front desk clerk himself for many years believes that front desk clerks holds a lot of power. They know the hotel and the rooms inside and out, and they decide which you will stay in. He says there is always a better room, and that the front desk agent is the one that makes the decision.
Since reading the book eighteen months ago I have tested this out every chance I get and it has worked out quite well – I pretty much always ended up with a better room and/or extras.
There is more information on my personal site.