A sub is a good thing for movies, no matter how good the mains are. Floor standers are designed for music, where very seldomly you find anything below 40 Hz. Musical instruments just don't go that low, maybe organs...
For a smal to medium room, I fully hartedly recommend Sunfire Dominator 8, currently on sale for $450 at audioadvisor.com. Thay are extremely musical as well, their bass is tight and accurate and are very small. Thay are a superb value. They rattle the house with moovies and complement the mains for music very accurately.

Point of fact: Mr. Mihaita is right that actual music hasn't very much content below 40 Hz, but that statement is about like saying that among all the music ever written not very much is by Bach or Beethoven. The fundamental of the lowest note on the piano is 27 Hz. Few piano scores include it, but any composer might agree it's nice to have it available, and a recording of a piece with that note, played on a concert grand piano, is going to be more convincing if the fundamental is audible on playback.
As for "maybe organs..." - yes indeed, organs. Bach used lots of pedal notes, especially for dramatic effect. I'm sorry for anyone who hasn't heard the Toccata and Fugue in D Minor and envious of any grownup who's hearing it for the first time, especially a live performance on a good instrument in a big space. (Talk about mind-blowing - !) And try listening to the beginning of "Also Sprach Zarathustra" (used in "2001") over a system that really lets you hear, as most theater sound systems of the time could not, that 32.7 Hz low C on the organ pedal.
Mr. Mihaita, I get Audio Advisor and maybe I've talked myself into following your advice on the Sunfire sub to go with my Magneplanars (lower limit 40 Hz).

I'm in total agreement with Mr. "psyprof1" (I'm sorry, I couldn't find the real name and be polite all the way) that my assessment about music carrying frequencies under 40Hz is rather quantitative than qualitative.
My intention was to say that audiophiles were happy with full-rangers for a long time, and the subwoofer in the home tends to be significantly more related to the home theater. Floor standers going down to 24Hz are fully capable of reproducing the fundamental of the lowest note of a grand piano, but they will fail (for they're not designed to) to reproduce the violent, coarse at times, sheer impact, low frequencies found in movies. LFE are a different animal, they're not music and have their definite role in home theater experience.
That's why I say "A sub is a must for home theater if the full impact of explosions and low frequency effects are to be had, but by no means a must for music, where good floor standers will shine". That's why it's difficult to find a good sub for music. Any sub can go "thump" and "boom", but by a large margin not all of them will be capable of a musical reproduction of the low frequencies.
When using the 1070 for music I can only imagine using analog inputs (coming from superior outboard DAC's) in stereo bypass mode, where the sub is out of the picture anyway and the mains are full rangers. Of course, 1070 may be used fed with digital signal for music as well, but then we're not talking audiophile grade DAC for the Cirrus Logic chip is not that.