For Baron Geddon the two mechanics that make the fight difficult is having to spend all of your man's and the living bomb. I chose a fairly standard mech mage deck because I wanted something to curve well and the spare parts help ensure you finish off your mana. The mage is also good at dealing with living bomb through hero power and spells that can be used on your own minions as often he won't have enough on the board for you to just trade into it. Save your spells for those occasions for the most part. Try and set up a big board and use Loatheb to try and finish him off without him taking another minion away. Good luck.