Hi y'all!

I haven't posted in quite a while and wanted to get some opinions on a good move up from the 170se that have been my mains. I also have a center 340se that I never used really, I really didn't enjoy it as a center channel and preferred stereo mode, with my sub. The sub I have is modest (Yamaha yst 10") and usually leave it off as of late. The question is what should I do now? I want a bit more fullness, but want to keep the clean imaging the 170s have. They did lack a bit when I pumped them for movies. I do about 70% tv time, the rest music. My amp is a Denon 1909 AVR which works well enough for now, I will probably replace it with a standard 2ch amp in the future.
So what should I do? I think I can turn he 340se center into a stereo and buy another center to also rotate. That's he cheapest solution but my reservation is I've never been happy with it; albeit it was center duty only. Another option is a b stock sierra if there are any left. The final option in considering is a hsu ccb-8, but the verdict is still out on them.
Are the sierras justifiable over 340s? How do other brands compare to the 340/sierra in this price range?

Thanks