We booked the golden circle super jeep tour plus snowmobiling on Langjokull glacier with Mountineers of Iceland. Sven our guide was amazing, such a friendly, knowledgeable and passionate guy who really made the trip the experience it was! I cannot praise him enough.
Highlights were the stunning volcanic crater (not usually included in the standard bus tours), the lamb soup at gulfoss, the story of the night trolls (saw loads!), the "detour" on the road up to Langjokull (what an amazing driver Sven is) and the most fantastic hour snowmobiling across the glacier (stunning views I would give anything to go back there!).
It is 100% worth the money for the memories you'll take home with you.