We're also considering centerpieces similar to these, though I'd swap out the tulips for orchids, calla lilies, or something else that I actually like. I would also use dark river rock, but I'd definitely keep the three vases of varying sizes and the curly willow.
Cylinder vases with floating Candle Centerpiece and Submerged Babys breath / Curly Willow
Tall Glass Cylinder with Curly Willow and Dendrobium Orchids
Tree center pieces at Aria! That's our venue! And with some orange too!!