I'll tell you what we're probably wearing since I have a DH going and kids. On formal night, myself and DD5 will be in formal dresses I may even opt for a long dress depending on what I can find in stores and DH will be in a suit and DS7 too, but only because we're taking onboard portraits and may use them for our Christmas cards.
On semi formal types of nights, DH and DS will wear button down shirts and a tie and khakis. DD will wear a dress more on the formal side or a princess dress.
Other nights, I'll wear a dress probably and because I have some already that I haven't even worn, but a night or two I'll wear nice jeans (no mom jeans) with strappy heels and a nice sequin camisole babydoll type top with chunky earrings and necklace and I'll feel totally comfortable and not out of place. DH may wear jeans one night with a polo shirt but probably more like on the first night. DS has a lot of polo shirts, so he'll wear those most nights maybe with jeans or cargo pants. We won't wear shorts in the dining room, but that's just us.
Hope this helps!