This is Lough Tay in the Wicklow Mountains in Ireland. This piece of land is owned by the Guinness family. The beach on the north shore is pure white sand which was imported by the family to give the lake a look of a pint of Guinness.
You can buy this photo at http://tinyurl.com/ccplybt or alternatively you can visit my Facebook page at http://tinyurl.com/bpmne4a The below HDR shot of Lough Tay can be bought at http://tinyurl.com/c6d9ra2
Thanks for looking!