For me:
Grades K-3
One World One God
Grades 4-6
Learn Teach Reach and You Can Change
Grades 7-9
Untitled
Grades 10-12
Murzik
I think the last one was the hardest for me to decide.
Murzik looks like something the actual Google designers would do. It is so cool!
K - 3
Music Brings Joy to the World
4-6
A New Beginning
7-9
Stop to Smell the Flowers
10 - 12
Murzik
I think Murzik would look just a bit better if the 16th note were turned down, rather than up. (Other notes might have to be rearranged a bit, of course.)
ETA:
That was what made it hard for me.
K-3
Music Brings Joy to the World
4-6
If I Drew the World
7-9
Cleaner Oceans for the World
10-12
I Wish
That was fun! There are a lot of very nice interpretations there. Talented kids!
K-3 - One World One God. Between that and Friendship Around the World. Nicely done. (Though in judging this group, I can’t help but think of this. I’m going to straight to heck…)
4-6 - A New Beginning. - This girl is an amazing artist for one so young. Let’s Heal the Planet was a sorta-close second. Reminds me of the GLOW flash games.
7-9 - Stop to Smell the Flowers. No real competition here, though Let’s Put Things In Perspective was kinda cool.
10-12 - Mursik. Hands down. Lots of good entries, but that one takes it by virtue of sheer creativity.
I’m a sucker for animal stuff. I picked all the nature-related ones.
K-3 Friendship Around The World
4-6 A New Beginning
7-9 Stop to Smell the Flowers
10-12 Google Graffiti
Thanks for sharing, Liberal. For some reason it’s getting me all verlempt. Great work by the kids.
K-3: Friendship Around the World
4-6: A New Beginning
7-9: Stop to Smell the Flowers
10-12: From the Ashes
You’re welcome! So, how did you vote?
K-3: Friendship Around the World
4-6: A New Beginning
7-9: Untitled
10-12: Murzik
It’s interesting that K-3 had the best designs.
Good Health for All
Work Together to Harness Wind
Put Things In Perspective
Murzik
Well, I got so choked up I had to leave the site 
I’ll take another look and report back.
Anyone else notice that region 6 has been pulled from gr 10-12? I think I voted for that one… it wasn’t in color, and had an owl whose eyes made up Google’s o’s.
Can anyone dig up info about that one?
Wait, nm, that was in grades 7-9. But the other one is still pulled. Was it there in the first place?