Alaska, New Mexico, Texas, and South Carolina

Let's bang a couple of these out.

1) Alaska
Yeah, it's blue and that's not real original, but this is an excellent flag that gets the blue right.  It is the deep blue of the sky, the sort of color where you would expect to see the stars.  The North Star is great for the most northern of all the states.  Ursa Major (the Big Dipper) shows the way to find the North Star and symbolizes the bear, yet another symbol of Alaska.  It also has a great back story, having been designed by a 13 year old Aleut boy back in the 1920's.  Excellent job Alaska, A+:

2) New Mexico

Another simple design with a lot of meaning and an eye-catching color scheme.  The symbol of the sun is taken from the Zia Pueblo, a native community, while the colors are taken from the Spanish who ruled the area for centuries.  It's no surprise it was voted #1 in the 2001 survey by the North American Vexillological Association and was the winner of the March Madness competition over at Vexillophilia:

3) Texas

Hard to argue with one of the most iconic flags.  It's on shirts, hats, belt buckles, cookie jars, bumper stickers, and on and on.  It has got to be one the most ubiquitous flags, and for good reason.  It's got historical connections, recalling the Texas Republic and Texas' nickname, the "Lone Star State," with its, um, single star.  Don't mess with success, or Texas:

4) South Carolina

One of the few other flags that is worthy of keeping the blue background, South Carolina's is historical, simple, and iconic.  The flag may have a bit too much detail in the center, but if a kid draws a white palm tree (yes, I know it's a palmetto, I'm being vague on purpose) with a crescent moon and colors it blue, there's no question which flag they're thinking about.  Now all we need to do is convince them to stick to this flag and the national one on their buildings: