Recently I have been inspired by Gaudasana, the eagle pose.  This asana is really good for focus as it is pretty much impossible to think of anything else at the same time as doing it without falling over.  It is one of my favorite postures as I love the sense of taking off and opening when I come out of it.  I have also been obsessed with birds and flight in my art work for the last while and so it brings out my imagination and sense of play in yoga.  Garuda is the steed of the Hindu God Vishnu and the mythic 'king of the birds'.  I recently also found out that Garuda can also be translated as 'devourer' and this refers to the all consuming fire of the suns rays (which eagles soar towards and also the fire or agni that burns within ourselves).  This works really well for me as this posture demands the mind to be devoured by it, directed inwards, single pointed in its vision.  Have you got a posture that you are observed with?