Argos in the UK are currently doing the MacBook air for £699 in the clearence for the new catelogue. The Air is the 11" 64GB Version, its the cheapest ive seen it at the moment. Worth a look,
http://www.argos.co.uk/static/Product/partNumber/5084667.htm
http://www.argos.co.uk/static/Product/partNumber/5084667.htm