Normally when I bring my computer between home and work, I shut it down. I mainly do this to prevent it from waking up, and have the drive jostled while it is spinning. The downsides of this are that it takes a long time to start back up, and I lose all of the current state.
I have started to used DeepSleep to put my Mac Book Pro in "hibernate" mode. In this mode, The state of the memory, registers and CPU state are stored on disk. When the computer starts up, this file is read, and the state is restored.