OPI Siberian Nights is a dark, dark cream purple. It looks more purple in the bottle than on the nail though, on the nail it was pretty much black.
It went on a little more thick than some OPI colors, but it was opaque in 2 coats no problem. I might try adding a drop of thinner just to decrease drying time. But I won't test the polish on my hands for a bit.
My camera doesn't do purples as well as some other cameras, but yes it really looks this color in person. (Unless you get bright sunlight then its more purple, but for most real life applications its virtually black.) That being said, its great for going under something that you don't want a straight black. I have pics coming Wednesday with this layered. Trust me, it is a world of difference. Holographic top coats, fun glitters, etc. If plain black isn't you, this color might be.
OPI retails for $8.50 and can be found at most salons. I can also purchase locally at JC Penny, Beauty Brands, and Ulta. Find authorized retailers at www.opi.com