Yep, which is why they'll often have constant green, pulsing green or blinking green as different status indicators.

Blue leds are mainly used for novelty value, it was the most difficult color to create in leds and now that we have them ... Some info here:

http://www.youtube.com/watch?v=yusrrOPM43o

A considerable part of the population experiences eyestrain from blue leds. They can induce headaches and when used in the bedroom you risk disturbed sleep cycles or difficulty falling asleep.