Just visited the Tower for the second time since 2004. I suggest you to be there about 15 minutes before it opens. Like this, everything can be seen without crowds and thus without queuing. I bought a London Pass for one day which (properly used) cuts the effective costs of many attractions (including Kew Gardens)to 50%. Some kind of discount is really needed, as the price has now risen to 17! pounds. Even for a Swiss guy this is a shocking price.