I strongly prefer a kitchen table. In our last house, we had a huge island that ran almost the length of the kitchen. And while we loved it for prep, I really missed having a kitchen table to sit out. I grew up where the kitchen is often the center of activity and I really feel like sitting at an island is not conducive to hanging out whereas sitting at a kitchen table is.
Of course, now we have a kitchen table but until we redo our kitchen, we don't have island -- and I really miss the prep space of an island!
In my ideal, there's an island and a table. (FWIW, I don't have kids so no real-life comments on how that plays into it, but to me, the idea of eating around an island is just not the same as a family eating around the kitchen table.)