My absolute favorite old school arcs are "The Deadly Assassin", featuring the Fourth Doctor in the only arc that features a Doctor sans companion thus far (to my knowledge, which is sadly less complete than I'd like it to be) and "The Caves of Androzani," featuring Fifth, and "The Black Orchid," also featuring Fifth. ...So actually, I guess I can think of Fifth stories I like and perhaps my brain was on stand-by last night? Hm.