The great thing about Home Audio is that it's all personal. So if you want to use a sub for music (I do - and I know many others that do also), then by all means, do it!
- the Pure preset on your remote face (labeled yellow) is playing the speakers directly how they sound with no type of EQ. I only use this when I first get my speakers to see how they sound and compare them to other speakers I have laying around. Think about it as - "it's purely the speakers"
- When I listen to music, depending on the genre, I usually listen in 2.1 stereo. That is done by pressing the Music preset on your remote (labeled red I believe) holding it down, and hitting the up arrow so the stereo option is highlighted - press OK. Some of my music goes well below 30hz and a sub is defiantly required. Even if I'm listening to mellow, or relaxed music - John Mayer for example, I still use my sub. Use the LFE as apposed to the LFE+main. I also brought my subwoofer crossovers down from 120hz to 80hz. I believe this is done by selecting the Menu (set-up)>Speakers>Speaker config.>Bass>click on 120hz and bring it down to 80hz. 80hz crossover settings are not brick walls, meaning that your towers will still play some frequencies below 80hz. Likewise, your subwoofer will play some frequencies above 80hz.
Sometimes when having my sub crossover at 120hz, I will feel vibrations of male voices which then becomes muddy and unruly because some frequencies of male voices are being sent to the sub. Bringing down my subwoofer crossover allowed me to "turn up the bass" for what it was intended to do and let my speakers handle deep voices (music and movies).
I would leave my speaker crossovers at 80hz, and leave them set-up as small - as you have. That basically means send the LFE to the subwoofer, which is a good thing. Less strain on your receiver, which lets you play your music/movies louder (bass drivers take more power to drive than tweeters).
Feel free to ask more questions or as me to clarify anything I might have missed