Since 2008, I've been compiling an annual master list of all the lists of best children's books; I include links to various newspapers, magazines, journals, and blogs, as well as different literature prizes and awards given out.
Another holiday treat is 150 Ways to Give a Book, MotherReader's gift guide that pairs up children's books and toys to give together. 150 ideas!
The blog of the English Department at St. Columba's College in Dublin assembles "a 'delicious list' of books of the year from a myriad of different publications and websites," which is terrific, too.
I update the big list all the time, and please, chime in if you know of some I'm missing.
Here are some recent additions to Chicken Spaghetti's 2011 Best Children's Books: A List of Lists and Awards.
Amanda Craig (great UK book critic).
BoingBoing Gift Guide. Includes quite a few children's/YA books.
Brain Pickings (Maria Popova's blog) Fun, eclectic list.
National Outdoor Book Awards (including a category for children's books)
Smithsonian.com: Just One More Story blog's "For the Very Youngest Readers"
Smithsonian.com: Surprising Science blog's Ten Great Science Books for Kids