Everyone has different needs when it comes to decks. I designed 100's of decks and none of them the same unless it's a straight forward deck.

Deck designs are based on the house layout, on individual's needs, deck exposure to sun/shade, etc. also the size of the family, do you entertain and do lots of cook-outs, or just to hang out from time to time, etc

The deck size will be dictated by your needs, budget and setback requirements or other zoning restrictions if any apply... other than that you can make it as big as you like and budget allows.

As materials go, there is IPE, Redwood, Cedar, Pressure treated and Composites (too many manufacturers to list). again it all depends on the appearance, your budget, and personal preferences.

As the cooking goes, if you do lots of cooking and Grill is not enough, an outdoor kitchen is an option, again if your budget allows and how much you want to spend on it and what you want to include in it, the sky is the limit.

As other toys go, if you plan to hang out and watch TV you will need a roof over it. If you want to have a fireplace and the deck is big enough and you have the room for it... it will not be an issue.

If you upload a picture of your back yard and some of your needs you will get some suggestions.

Good luck

Definitely going to be checking back on this one as I'm getting ready to build a deck too. Wanting to go with a natural wood and some area for a bbq