Our garage plans are in the early stages still, but we have decided to do a garage attached to the house. As we progressed with the detached garage concept, it created many issues including dead space between the house and garage, losing more space on the south side of the garage for a garden area and it would have required moving our current retaining wall in order to get a car into the far south bay. The attached garage will be slightly more complicated to build (specifically the wall that butts up against the house will require more attention) but much simpler overall when you factor in the problems it doesn't create.
I never thought I could be so excited about four walls being built, but I cannot wait until this project is done. A garage to park my car in and a roof deck to park by butt on. Life will be good.