Children under 5 get a giant Christmas card, the kind the whole office is supposed to sign. Little kids never get mail, so you'll make their Christmas. Give parents cash to get whatever the kid actually needs.
Children 5 to 10 get a GI Joe or a Barbie. Doesn't matter if the kid likes that toy, what matters is that they can trade it in the school yard. It's like sending someone in jail a carton of Newports.
Ages 10 to 20 get cash.
Over 20 gets a nice bottle of booze. Even if they don't drink, they can regift it easily.
I bet that 8 year old would have an easier time trading a nice bottle of booze.
Seriously, though, my parents would have been pissed if I traded away a gift someone gave me. We did trade stuff all the time (mostly matchbox cars and baseball cards) but "I got this for Christmas" meant that it was off limits for trading.