Some of the best and highest skilled Hearthstone games are streamed by 
Thijs during the day. He tends to play a different deck or two each day and this is the Thijs Giants Yogg Portal Legendary Mage Deck he was playing recently.
There have been a few Tempo Mage builds with the new Arcane Giants but I like this list best so far. It slows the game down a bit and gives you time to lower the cost of the giants and control the board.