Speakers for my room

Room is 15 foot cathedral ceiling. Glass on one side at about 20 feet depth. Other side opens to a kitchen. So it's pretty big and I have rather inflexible placement options. I currently own an NAD 326bee but could potentially upgrade. We listen while moving about, off axis and sometimes 20 feet directly away on a couch. Source equipment is rather low end both digital and vinyl. 
We listen to classic rock, female and male vocals as well as some newer stuff like tha Alabama shakes. We are not huge bass heads. 
I would like to find some speakers that do well when one is away from the sweet spot. I would love a pair that I can hear details even at lower volumes. I'm not opposed to used. 
I'm a bit of a mess trying to decide. I've considered bookshelves (Kef 300 and ls50, Nola boxer and Polk lsim models) as well as Towers from psb, vandersteen ( 1ci) and KEF. 
Any advice?