After your big meal, avoid the wide-angle table view. The distortion will make you family—already fat and happy—look even fatter. Instead, make a more natural and flattering photo by shooting each person individually at about 50mm.
If you need flash, use a hot-shoe unit turned backward and slightly up, so that the light bounces off the wall behind you (bounce it off the ceiling if the room has dark walls).
Now that you have all of these individual shots of everyone at the table, use basic panorama software to stitch them together into one big, happy photo.