I currently have a good pair of Bookshelf Speakers and am considering an upgrade to a pair of Full Sized speakers to get a fuller music sound in my party room (exclusively 2 channel listening)

I would like opinions regarding how the sound of a pair of full sized speakers may compare to the alternative of just adding a Self Powered Sub-Woofer to the B speaker outputs of my amp and having this complement the sound of the Bookshelf Speakers.

I know that listening to speakers is the only real way of auditioning them, but I dont have any good stereo shops close to home and I travel a lot, which limits my testing time.

I would like to have a few opinions before i go out and pick up equipment to come try at home.

Thanks for your help.