Yeah, I had this exact issue with the Galaxy series (not Galaxy II, which as martythemaniak mentions, fixes it) and mentioned it in my review. Some people simply don't see it, though, it really amazes me. I can't NOT see it.
The Samsung Galaxy S2 uses a non-pentile OLED screen, so these screens are on their way out. I have one of these on my Nexus One and the only time it's noticeable is when you use very small red text (8sp IIRC).
That's possible, but green has been the color of the Android logo, mascot, etc. since very early on, so the switch to green in the UI makes logical sense from a branding perspective.
Also, I think Samsung is the only Android phone maker still using AMOLED displays (they control the supply), so that seems like a pretty big concession to just 1 handset maker.
