Green doesn't look good with my skin tone, so I wouldn't buy the green one for myself, but since I'm not actually going to buy any of then, I do like looking at it. If I wanted to spend stupid amounts of money on a diamond, I'd look seriously at a pink one, but I have other places to spend money foolishly.
One of my birthstones in blue zircon, which is naturally radioactive. You don't see it much any more, but it was popular in the early twentieth century and you see it in vintage jewelry. I think it's very pretty so, a number of years ago, I thought of buying myself a vintage blue zircon ring. Then I thought about the history of really aggressive cancers in my family and decided that my crappy DNA didn't need to be in contact for long periods of time with even a slightly radioactive stone.
When we bought my engagement ring, we were looking at the usual white diamonds to be set in a rose gold ring that I really liked. They had a couple of loose diamonds on display and one of them was blue. It was a pretty color, not unlike the blue zircons I'd admired, but the diamond had been irradiated to get it that color. I don't think there would be any residual radiation, but I just didn't want my engagement ring to be "fake."
Next to it, there was another colored diamond. This one was brown, which I would have never thought I would like, but something made me think it would look nice with the rose gold setting. It did. In fact, it looked so nice that the person waiting on us got a little excited. So that's what we got, and I'm still very happy with it.
There are mines in Australia that produce brown and pink diamonds, so I like to think that perhaps the labor practices are a little less oppressive there than at the blood diamond mines in South Africa and thereabouts. It's my understanding that some of the brown diamonds from those mines have desirable pink overtones. The official description calls it "fancy very light brown" and doesn't mention pink, but I see pink in it.