regarding bookshelves vs floorstanders: I have a varying opinion compared to others here, shaped by a very limited timespan of experience, but with considerable intention. Anyways, to repeat: the following represents only my opinions.
I heartily agree that an excellent sub is key to the HT experience. No denying that. However, I find with some lines of speakers that a pair of bookshelves + a pair of half-decent looking stands costs the same as the towers from the same line. To the best of my knowledge, Dolby and DTS send out full range signals not just to the mains, but also the surrounds. So, ideally, one would have 7 towers. Ok, costs and practicality come into play....
The ONLY reason I have bookshelf surrounds and rears was to be able to put them on very tall stands to have the speakers fire over the blocking furniture. If a typical tower had a tweeter placed high enough, the decision would be a no-brainer for me. Towers w/o stands would have been identical in price.
I have yet to hear a bookshelf that does not give it up in the mid-bass region (let alone the low-bass region), including multi-thousand $ models from Focal, B&W, etc. I have some PSB Images for surrounds, that go to 45hz(-3db) on-axis, which is very good for a bookshelf (one of the reasons I chose it, as I believe digging deep is one of the few things I look for in an HT speaker; and I find HT to be 100x easier than music). My surrounds can crank for a bookshelf, but still wouldn't have the same slam as the matching towers.
Pure speculation on my part, never having tried it. Even if one had towers and bookshelves to compare in the same line of speakers, and x-over'd both at say 80hz, Id bet the towers would have superior mid-bass (slam) performance, especially in a large room. Seems yours is medium sized (iirc), so perhaps not... Running towers vs bookshelves both at full-range, no contest.
The other helpful posters here may very well be more correct than I. It is simply my present opinion.
