Another thing my group would find very useful is a button the DM can hit to stop players moving - ie. cuts all player permissions to move tokens. Most commonly needed when players move from 'exploring' mode and enter combat: eg. players are moving around the map, then one of them walks into a trap or a room full of monsters. DM can hit the 'HALT!' button and then combat commences with the rest of the party in whatever position they might be when that combat was triggered. Once initiative is rolled or DM describes the scene, he then gives the players control of their tokens again.