Sounds like you have a nice setup already... why do you feel the urge to "upgrade?"
That said... perhaps a modest sub just to catch that last little bit of low bass, something like an SVS, which has customizable integration so it's all smooth.
Otherwise, it's usually the speakers to look at first, if you're not satisfied. And, tech has gotten so good that you don't need to spend the entire 10k... See if there's another type of speaker sound you like better: perhaps the new KLH 5 or the widely heralded Polk m700. the Polk is about 2k, and likely has a different sound character than your Warfdales... like the KLH 5s also. These are not outrageously expensive speakers, but are the sort of product that just might "finish" or at least tamp down that urge. Or what about the 10k top level Warfdales, the Elysian? If you wanna drop 10k, why not those... ? But you can actually test drive those Polks or the KLH 5, if you buy 'em from Crutchfield.... they have a good return policy if you're not satisfied.
Please whatever you do, don't blow that cash on fancy speaker wire or interconnects... you can do a lot better looking at the speakers themselves, first.