I think this is a basic one to have in the repertoire. Its quick and easy and everyone loves it.
I take a whole chicken and butterfly it (your butcher could do this for you if you ask nicely). In a roasting pan lay out some lemon slices and place the chicken on top, skin side up. Into the skin rub some olive oil then sprinkle some salt (I use garlic salt) and some dried oregeno. Then place in an oven (middle rack) preheated to 220C for 45 minutes. Remove from heat and rest it for 10 minutes before carving and serving.
Note: You can use the pan juices and the 10 minute rest time to make a lovely gravy.