Make certain that you have a railing system that is a sweep-through, not with the spindles/pickets attached to the deck floor. Makes life so much easier for owners and contractors alike :)

Make the size fit your needs,if your thinking cover goggle up Shade Sails I love those things, benches in the right place make for a nice area,alum balusters are a good idea.

A built in fire pit is a total confort thing same with a grill area but I think an outdoor kitchen is a little much. Lights under the bottom rail of the handrail, Deck with S American lumber or a high grade Composite--Moisture Shield, TimberTeck.--

Last year the payback for an outdoor area in the US was 114 per cent thats better than kitchens/bathrooms start out with everything you want,if its too much for the wallet back off from there. J.

The average payback nationwide on a deck is 73%. Just google it

We love our built-in cedar slab benches. We also love how the deck now joins our garage door with the house back door. Finally, we love the bright multicolored look of our redwood decking in the rain.

Thanks for your responses. Any others?

Here are some pictures of my deck that was just built. I really like the look of it and its maintenance free.
decksummer08.shutterfly.com

Think about your family and lifestyle. If you have small kids or big parties, a built-in bench might be nice. If it's mainly a small number of adults, you might be happier having more floor space for comfy chairs or lounges. If you do a built-in bench, think about having the seat lift up for storage. Think about the railing, both practical aspects (maintenance) and esthetics. Do you want posts, perhaps with post cap lights, or all flat board all around. Will you be hanging planters or window boxes off it? Consider lighting, especially if you'll be doing things like grilling after dark. A power outlet handy to the deck is invaluable. Plan the exits carefully, this can make a big difference in how convenient it is to your yard as well as the house interior. Think about the time of day you'll use it and how sunny it is at those times--will you need to build in a pergola or awning? There are SO many variables!