I'm starting to build my system. I'm still a bit unsure of the real differences. In general, which one sounds better and do you prefer? I have an H/K 630 and Polk RTi100s right now. Would my money be better spent on polk's FXi 5 bipole/dipole for the 5.1 system, or should I get monopoles and run it as a 7.1 system? I do have an old pair of BAs (HD5Vs) which I could use as well. Any thoughts?