Thinnes Quality speaker cable?

I'm making changes to my HT setup, and wanted to replace my ridiculously thick (1") MIT MH-750s3 speaker cable with something thinner and more flexible, especially for the rear channels. While I'd like to maintain the quality aspect of good bi-wireable speaker wire, something thinner would make things easier. I saw Monster makes a 16 guage flatwire but I wasn't sure if this is any good (at least for the rears). Any Ideas? Is plain old 12guage wire just as good.