Marble is a big investment, but without exception marble dining tables are nearly always showstoppers. Tables crafted from quality imported marble are extremely beautiful.
Black tables are notoriously tricky, especially if they are veneered, because the smallest scratch will show up. If you are the careful type, however, black is super cool and will always be so.
Settle on a shape that will work in most rooms. Round tables look good in compact rooms and living areas that have square dining zones. They also offer flexible seating.