We have an oval kitchen table with a bench on one side and chairs around the rest. Benches without backs can be handy when kids are small (you can squeeze a lot of kids onto benches and benches take up less space). Few adults, however, seem to want to sit on the bench for very long.

Also, although there are some benches made to work with round tables, most benches are used with rectangle or oval tables. I like a round shaped table in your kitchen.

Have you thought about just a bigger round table. We have a very similar layout and we have a 54" round table. For daily use it's only four chairs but I can fit up to 8-10. 6 fit very comfortably.

Your current table is lovely. But it doesn't have leaves? I'd suggest something like it but with a leaf or two. Delta put it well -- kids are fine on benches but we adults steer away from them given a choice.

I also think a bigger round table would look nice in your space.
I'm planning to get a rectangular table with an upholstered bench in our kitchen area. But the bench will be up against the wall (like a banquette). In your room it seems the bench would be floating in the middle of the space. I think in that situation chairs would just be better.
If you do decide to go with bench seating I would try to find a trestle or a pedestal table. It makes access to the bench easier.
Good luck with your decision!

Our dining table has a bench (with a back) on one side and 4 chairs (one of which is missing in this pic!).

If you use a bench it should have a back---I don't see why children should be less comfortable than adults. An oval table and two more chairs would do the trick, and I like your current black for the table.

I think that a dining table should have comfortable chairs. Benches are the worst! No back support, you are sharing with other people so you can't pull the chair to your comfortable distance from the table. PLEASE consider a set with comfortable chairs, or purchase them separately. Many furniture stores sell them chairs separate from the table, find a table you like and then find chairs that go with it. Make sure there is room for the chairs under the table if the table has a drop underneath. Dining should be a comfortable experience, not a torture chamber, even if it is just for the kids!

I am with Kswl on every point, including the black for the color.

Have you looked in our Kitchen and Dining Room threads and our Show Me Your Cottage Decor threads in our Gallery? There are tons of gorgeous pictures. It's like gettting a whole ton of magazines free.

Here is a link that might be useful: Gallery

Another note: why not keep the chairs and just get a new table? If you can't get the same chairs, get 2 new ones in the same black finish (we have some from LL Bean that I really like -- we use them with their farmhouse table).