i tend to like the stuff that's less pompous, and more focused on songwriting, in whatever abstraction - or more psychedelic. so, i like genesis, crimson, floyd - although i actually prefer oldfield, or tangerine dream, to the bulk of it.
i tend not to like the geekier or more randian stuff, like rush or elp or zeppelin.
and, when you bring the macho poseurism or show-offism that is more indicative of metal than prog in, i just tune out altogether. so, i just can't get into stuff like dream theatre or slayer for that reason, although the major problem with later dream theatre is less that it's too metal and more that the singer just ruins it. there's a short time window of dream theatre stuff that i've found instrumental japanese imports of, that i can actually get into.
so, i made fun of him for listening to hair metal, too. i didn't just take that shit.