The rule of thumb is you want between 24 and 36 inches from the table's edge to the wall in order to have enough room for a chair and to walk around. I generally prefer rectangular dining tables unless 1) it's a square room, 2) it's a rounded type room like with a bay window, 3) it's a small space, or 4) it's an informal space like a breakfast nook.

Thanks for the advice this really helped be out a lot.. cpaul1