Yoghurt as a marinade base - sounds gross, but tenderises the chicken beautifully and doesn't end up tasting yoghurty at all. just use a few tablespoons of plain natural yoghurt as a base and add whatever seasoning / spices you like.
I do a slightly spicy version by add a few teaspoons of curry powder to the yoghurt, marinating the chicken breasts in it for at least an hour (preferably 3-4 hours) and then grilling under a hot grill. I also do a version where I substitute the curry powder for a big glug of sweet chilli sauce and a little bit of lime zest. Both work really well on the BBQ, too.
Very quick and easy one - put chicken breasts in an ovenproof dish, pour over a jar of good quality tomato-based pasta sauce (the Jamie Oliver ones work well for this, or you could make your own of course. Add black olives to the sauce if you like them...), then top each breast with a thick-ish slice of mozzarella cheese and bake in a hot oven. Garnish with fresh basil leaves. I serve this with lemony potato wedges (red-skinned potatoes, whole garlic cloves, lemon wedges, bung in oven for 30-40 mins) & steamed young greens - spinach, peas, tenderstem broccolli. really nice.
Have you tried making jerk chicken? Or Thai green/red chicken curry? Or an Indian-style chicken curry? Or BBQ chicken?
Can you tell I love chicken?