This is our packing list of what we took (for one person) to Quito and the Galapagos during our two week trip. It also has notes at the end of about suggestions that we learned after being there for two weeks.
Suggestions to add/subtract: We definitely did not need the dress shoes or dress shirts as the dress code on the boat and throughout Ecuador was casual. The collared travel shirts easily doubled as nicer evening shirts, assuming we kept them fairly stain and dirt free. We also did not need the Tevas (which we brought for wet landings) as we could go barefoot for the wet landings and then change into our athletic shoes for the walking portion of the excursion. We wore flip flops constantly on the boat and in Puerto Ayora and wore our athletic sneakers everywhere else in Ecuador when we needed closed toes. Also the walking/hiking tours in the Galapagos were not overly challenging and hiking boots are definitely not required.
I would recommend having appropriate exposure protection (a 1mm skin or more) under your wetsuit if you are prone to getting cold. I also recommend Lavacore for those of you who want a great rash guard/skin alternative. See here and here for options.
We rented almost all of our scuba diving equipment but brought our own mask, snorkel and dive computers but could have easily rented this for our scuba trip and the Eclipse like most boats had snorkeling gear included for passengers. If you do not have any of your own gear or don’t want to pack it, don’t worry you can find it easily for rent.
We did not need the netbook but I would recommend it as we took hundreds of pictures per day and it was nice to have so that in the evenings we could review and edit photos on the fly without having to sort through thousands when we got home.
The underwater cameras were great to have and it added immense pleasure to the trip to record videos and photos of the scuba diving and snorkeling trips. If you want a recommendation on cameras send me an email and I will provide you details on what we used.
Sunscreen was essential as a few of us can attest to the power of the sun at the equator and I would recommend Bonine/Dramimine/Meclizine for seasickness.
The North Face Duffel was nicer than a rolling suitcase as getting off and on the various modes of transports was not wheel friendly and the backpack feature of the duffel proved to be very versatile.