The day I was ordering my CTS, they had a STS on the showroom floor in Sunset Blue. I expected more of a blue but it had one of those colors that looked blue or green, depending on the way the light hit it. I didn't see it outside. I wasn't real crazy about it.
I saw the sunset blue in the flesh on a couple 08 CTSes yesterday, i totally loved it actually, i think its got more blue than the current 07 sunset blue (which i always thought was silver). my mom though was like 'thats too old a color for you.' so i dunno, im 22, otherwise id personally go for it (and i dont think it actually looks old)