Questions about my Polk Audio Purchase

I recently purchased the Polk Audio RTi6 bookshelf speakers... which will probably be used as my rears, and getting either the RTi10s or RTi12s for my front left/rights.


Thing is, at the time I thought I'd be using my RTi6s for my fronts and FXi5s for my rear, now I've changed my mind.


I've read a lot about surround-specific speakers being better for music than direct radiating(?) speakers in an article on Paradigm's website...do they mean for the rears? Or do they mean "surround" as in on the side for a 7.1 setup?


Did I make a mistake by deciding to replacing my fronts with RTi10s or RTi12s and using my direct radiating RTi6s as my rears?


I'd say my interests are 50/50 for music/film. DVDA and SACD is also a pleasure I hope to indulge in and appreciate also when I get the equipment.


I assume that when I can afford to buy a 2 more speakers to complete my 7.1 setup that they should be the FXi5s at that point, right?


I really want the ideal Polk setup and hope that it can include the RTi6s that I already purchased.


Oh, if I have a 7.1 setup w/ FXi5s on the side, those won't used at all for music will they? Currently 5 speakers is as high as it goes for music? There's no 7.1 DVDA discs are there?


Thank you,

Laura