If I've had a lot of people over, I do a pot of chili in winter - you can make veg chili as well and in summer I do hamburgers and hot dogs
For parties I've also had trays of sandwich meat (antipasti) and cheese with lots of rustic bread and let people make their own sandwiches. That way, it cuts down on the work before hand and if there are leftovers, you can actually use them. Then veg and dips. Hummus and pita is a good one too. Don't make fruit salad, just cut up the fruit. You can also get the frozen appetizers at sainsbury's. Oh and don't forget the sausage rolls and the cheese and onion rolls - It isn't a party without the rolls!!