I like the Green/Green, that is mostly what I see. I have them on my Sig and G17, and had them on my G36 as well. I really like sights where they are spread wide apart, so you can see on the sides of the front blade even when lined up with back sight.
Before you buy, you should also look at XS Sight Systems, they make an interesting night sight called 24/7 Big Dot. I had this on my G26, pretty interesting "lollipop" design, where you put the "dot" (front sight glow) on top of the "line" (rear sight glow). I liked them, they are perfect for up close self defense, but forget about shooting for accuracy or grouping. They are just too big for that, they are solely for quick acquisition.
Another brand, my favorite, that you should look at is Heinie. They make the Heine Slant Pro Straight Eight sights, which are amazing. Really wide back, thin front, and the rear sight only has 1 dot centered, and so does the front sight. You just line them up to make an "8" and you are good to go. In this way, you can't get confused as to whether you are centered correctly.
The reason they make night sights in color combinations is the fear that in the dark, you may accidentally put the front sight to the left or right of the rear sight, and then think it is lined up (3 dots if that happens, under stress it is hard to tell that spacing is off). The sights from XS and Heinie eliminate this problem by having glowing portions that are impossible to confuse. Both these manufacturers can be found on the web, and I've ordered from both without problems. I love the Heinies, I wish I had them on my current firearms, I'm thinking about getting them when I get some cash.