This question comes up for me most years.
My kids have plenty, they are not spoiled (imo) but have items that just are hardly used.
For example, my daughter was given a "Groovy Girls" set a couple birthdays ago with two cute dolls, a clothes chest and dozen little outfits. She never really took a great liking but it has remained well-kept in her room. (I do the 'well-kept' part).
(btw I used to intercept many of the excess toys given to the kids when they were younger and they didn't notice to regift, return or donate later...this is much more diffucult now though as they are older)
Some books, puzzles, and other toys fall into this category as well.
On Monday, my next block of free time, I plan to go through the kid's room with them and remove with their permission all these items in anticipation of making room for new things from Santa.
SO---------
My preference is to give the dolls, for example, to a girl who really wants and wouldn't otherwise have such a toy.
How?
I am contacting the Boys & Girls Club first. I am not a churchgoer, and have no contacts in that department (unless through a friend). Last year a County Children's agency had a room where families could come 'shop'. They are not doing it this year due to staff cuts 
Instead of giving to the thrift store (who would make some money on these), or Toys for Tots (who probably won't take a used toy anyway) I wish it to be more personal if possible.
This comes up almost every year. I need to find some solution.
Where To Donate the Barely Used Toys?
December 20th, 2007 at 07:02 pm
December 20th, 2007 at 07:11 pm 1198177893
December 20th, 2007 at 07:28 pm 1198178916
Clothing and shoes for children are also greatly appreciated.
December 20th, 2007 at 07:40 pm 1198179611
December 20th, 2007 at 08:12 pm 1198181520
I haven't found anywhere else to take them. The shelters and everthing else I Can think of want new/packaged toys.
December 20th, 2007 at 10:10 pm 1198188654
The mom shelter was nice but couldn't handle it this late, and others want the toys new.