I'm not mad at the antipasti platters idea. Yes, they're done a lot, but that's because people tend to really enjoy them and they're really forgiving when left out for several hours. You might also consider another crowd-pleaser, bagna cauda. It comes together in minutes, can be made in quantity in advance and hit with a squeeze of fresh lemon upon reheating and you only need to put out some fresh veggies and bread for dunking.