I have lumia 800 which has a pentile isplay, which means that some colours give a crisper edge to the tiles and some give a fuzzy edge to them. On a black background, the dark green give the crispest edge (but it's not a great colour) and any of the red-ish colours (that's anything from orange to purple) give the fuzziest edges. I use Cobalt Blue on a black background most of the time. It gives a crisp vertical tile edge, but a fuzzy horizontal edge, which I can put up with. I won't ever get a device with a pentile sub-pixel arrangement again.