Ivory. Go with the ivory. To really make it "click" - get some old medallions from Numrich's or a gun show, and inlet the ivory a little with a forstner bit and mount them. That would look great and really "tie" the grips to the gun.
I don't like the wood because they scream "cheap" - laminate wood just isn't real wood to the discerning eye. I think ivory, real or fake, can look great with either stainless or blue. I DO like the look of that Blackhawk with those fake ivory grips.
A tip - I fit some fake ivory grips to s S&W 19 recently. I did some shaping to them to get them just perfect on the frame edges. When I was done, I wiped them down with 3-in-1 oil and a little soaked in, bringing out some texture and making them look more "aged" instantly. Try that if you like. I also got some medallions and will be installing them, too.