My deck is only 10' x 12' It is sufficient for a table for 4 because you need at least 3' on all sides of the table to be able to move around it. Your 14' length allows for a longer table, but you need to allow 4' between the table and the door to the house. If you only want chairs figure about 5 square feet per chair. You still need to allow space in front of chairs for access. Let's say your main walkway between the door and the yard off the deck is on one side of the deck. That leaves 10' for seating (14' minus 4' for access). Use a loveseat on one side and two chairs opposite. This gives you a roomy 4' between the seating, and in this case I think it is better to provide end tables for drinks. The deck will feel cozy but not restrictive. This applies to both a 10' and a 12' wide by 14' long deck. The 12' deck would allow you to use a narrow coffee table in front of the loveseat. In both situations you would likely have room for a chaise at the end of the seating area where its longer length wouldn't interfere with access.

Neither size is good for adding a grill. It's not just the size of the grill, but the fact that you need at least 3 ft in front of it for access. If you want an outdoor grill consider adding a paved area off the deck for that. Another thing to consider about the size of a deck is how they are built. Decks often have one side of their floor joists sitting on a ledger board attached to the house. This is fine for small decks, but large decks with lots of furniture are more likely to fail. Decks higher than 4' become DANGEROUS should they fail. Your deck does not seem dangerously large to me, but overloading is always possible, and people seldom think about the weight of furniture and plants much less adding a lot of people during a get-together.

Thank you so much! This was a very generous post and it helps immensely. A small table or a couple of chairs is all we would need. Good info about the grill, ours is currently on the patio and it can just stay there. The deck would be about 3' high (maybe a little less), but again thanks for the info on the strength of the deck that's good to remember. It doesn't sound like there would be all too much difference between 10' or 12' though I do plan to mark it out just to get a sense of the space. So you've given me a lot to think about. Thank you kind internet friend!