We have 3 kids: 16, 13 and 8. The last few years have been leaner since I am now working a job at less than 1/2 the pay of the one I used to have before I was laid off.
I try to spend about the same on each child, but it is too hard to keep to the same number of gifts since the older kids gifts usually cost way more than the things the youngest wants.
The kids get 1-2 things from mom and dad and 1 thing from Santa (usually the big gift). They also each get a gift from each sibling. We give the kids $40 to pick out the 2 sibling gifts they each buy. Honestly, this is one of my favorite traditions. It is fun to see the things they have picked out for their siblings. Sometimes it is something the sibling has asked for, other times it is something that they "just know" that the sibling will enjoy.
And Santa always brings a family gift. Most of the time it is a movie, but last year it was a cake pop machine!
We used to spend alot more money on Christmas, but these last few years have been leaner by necessity and it has made dh and I realize that for us, spending alot more at Christmas really didn't make for a happier Christmas. A good lesson for us to learn.