If you fall in love with a metal or marble table, don’t be discouraged from buying it, but do think about how you might safely transport it. As suggested above, choose a small, round marble table, or go for a wooden table with detachable legs.
If you want to be more flexible with your guests, pay attention to the leg width and where the legs are placed. In general, a table with thinner legs, or where the legs are at the corners, will make it easier to squeeze an extra chair in.
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.
To visualize how a bigger piece of furniture will look, take the time to block out the length and width on the floor, and also the height of the table. I usually stand on my tape corners with a tape measure, then try to fill in that space with furniture of a similar size, and take a step back to see how it’ll feel. It also helps to have a friend stand there with the tape measure while you have a look.