It wasn't a big shock, but anyone who didn't have a lump in their throat watching Nancy and the children hugging next to the casket must be without a heart.
To answer the Nixon thing: Yes, the mail stopped when Nixon died. Nixon had the oppurtunity to have a full State funeral similar to Reagan's, but refused it before he died. You see, the markets closing and the mail stopping was not directly caused by Reagan's death or funeral. It's because the President called for a National Day of Mourning. The NYSE has in their by-laws that when a NDoM is called for, they will halt trading. The USPS has in its Union contract that they will get the day off. I'm sure other Government workers union contracts are similar.
I don't really understand the "Big 3" carrying the funeral either except that they felt they would lose out viewership to the cable networks or would piss off a lot of "Reaganites" by not covering it. It all comes down to money, even with the coverage of a funeral. Fox News was wall to wall Reagan all weekend.