Well, we did it ... we're a month into our remodel, and it's coming along nicely. We're adding over 700 sq. ft. to the back of the house, and as of last night, it's all framed in. We were actually able to walk through the addition from room to room and really get a feel for what it's going to be like when it's finished. Very exciting!
Yes, adding on is a stressful business, but I'd still recommend it to anyone who loves their neighborhood and their house, but just needs more room. The thrill of seeing something you designed come to life before your eyes is well worth the endless decisions and the unnerving aspects of trusting someone else to run the project. Hopefully I'll have some pics up on Flickr soon.