To recap a few of the replies I've seen:
1) Regardless of any sonic advantages, I choose to use tower speakers because I think that spending money on stands to get bookshelf speakers at the correct height, with the end result being little speakers balancing precariously on stand looks out of place and wouldn't want it in my room. Floor space is the same, and a normal speaker(towers) look better. This point is of course simply opinion.
2) Tower speakers crossed at 80 Hz to a pair of good subs are better than a pair of small single woofer bookshelves crossed to subs. Larger, multiple woofers will play the 80-300Hz region with lower distortion and higher fidelity than a small, single woofer bookshelf. They struggle in this range, especially since this is where we need to apply eq if the goal is high fidelity. Eq eats up headroom and requires even more capaility in this demanding region. Look at almost *any* bookshelf speaker and how soon they distort below 300 Hz even at low SPL at 1M. Now try adding 3-6 dB of eq…….
3) Despite this being a forum focused on the objective pursuit of high fidelity, it amazes me how many think turning their subs off for music is somehow higher fidelity???? If you have poorly placed, poorly integrated, and or low quality subs, maybe.
4) It has nothing to do with subs or no subs. For those whose goal is high fidelity sound reproduction, bass managament, dual subs, and eq are all but required. 2.0 channel is, for practical intents, low fidelity regardless of how much we imagine our 120 dB signal chain improves what we hear. What we DO hear is the train wreck, low fidelity response of a 2.0 channel setup in a room. Towers with subs are better than bookshelves with subs in most cases. Lower distortion, lower extension for better integration around crossover(even at 80 Hz), better looks, and better ability to play louder if you ever want to, even if occasionally.
5) If people sit close, or listen at low enough levels, or just prefer small speakers balancing on stands, thats ok too. But objectively, towers with subs are better than bookshelves with subs in several ways.