Hi. Decks are always an exciting expansion of the usable space of a home. A very useful mod!

In my previous remodeling business, I had 5 copies of Sunset's "The Complete Deck Book" for my client lending-library. Everyone who incorporated decks into our projects really enjoyed it. It is a bit heavy on redwood (hard to resist for the pics) which may not be in common use in your area, but the designs can be carried out with cedar, Trex, or any of the other myriad options.
http://www.amazon.com/gp/product/037...Fencoding=UTF8
Some of that content may be available on the publishers website.
BTW, if moisture is a concern, I'd also recommend a under-deck fastening system, rather than having exposed nails of screws. It used to add a lot to the cost, but now that many systems are made, I think it should be considered standard practice.
Last, have the builder pre-treat any wood in the installation with sealer. Some of the decks we installed are just having their first reseals after 10 years because of that step, while decks without it often need retreatment every year. YMMV based on your weather conditions, of course.
Happy designing &