Sorry to bump an old thread, but are these rules for the groom/groomsmen or all guests? The presumption being it is not a black tie affair for the guests but you're in a suit. I have a friends wedding coming up this week and was planning on a charcoal suit, white shirt, and navy tie. The tie I have in mind looks like this but in a dark navy:
The last wedding I went to was a spring wedding and I wore a lavender tie with white pin dots - but I was trying to spruce up then for the season.