need advice

Hi all,
Have an older system that I bought back in the late 80's
which I'd like to update for better quality sound.
The receiver is an Onkyo TX-840 60 watts per channel matched up with a set of early model Bose 401 floor standing speakers. Was wondering if you had any recommendations on upgrading my speakers (say maybe $600-$800 for a pair..used would probably provide best bargains)that would give me a better sound than the Bose 401s. Okay with staying with a two channel setup. Mainly listen to CDs and vinyl (all types jazz, rock, blues, etc).
I love the sound of the B&W and Paradigms, and I've some models used for that price range. Not sure if I should try bookshelf speakers on stands (since they might be cheaper). The room that the stereo is located is 20'x 12' with a sloping ceiling on one side that's two stories tall. Hardwood floors with rugs.
Thanks for your thoughts.