I like make-ahead things, especially something like a boeuf bourguignon or coq au vin or other stew that can be made the night before, and is usually even better the next day. Ditto for a soup such as vichyssoise - make the day before, and add the milk or cream when you reheat it. Focus on quality ingredients.
For dessert, I make an apple crisp: put fresh apple slices into a baking dish, sprinkle with a tiny bit of lemon juice to stop the apples from going brown, then top with a mixture of roughly equal parts of oat bran, flour, butter/oil, sugar to taste (we don't use much), a sprinkle of cinnamon, and enough water to make a very thick paste that can be flattened by hand into patches to apply as a top crust. I do all this before people show up, and toss it in the oven when the stew/soup is reheating. Takes about 45 minutes to an hour to bake at 350. Serve warm with ice cream or gelato, or on its own.
The Silver Palate cookbooks were a great inspiration.
IMO, the best dinner parties are the ones that don't involve a lot of last-minute prep, leaving you free to actually enjoy yourself.