I don’t think a topic like this has been made already, so I’ll go ahead and post it!
My current board style: Wall-E
Me: Up.
You know why… 
I’m using the cars one, I am not a huge fan of the film i just like the colour
Up
Asking why would be a bit silly
“Monsters, Inc.”
Wall-E for obvious reasons.
I was using Monsters Inc for the longest time, but now I am using Up. 
Wall-E. I guess partly because the Upcoming Pixar blog still doesn’t have a Wall-E themed background yet, but mostly just cause I love that movie so much.
Still Incredibles. Been that way for almost a year and a half. Sorry Ratatouille, but nothing brings me more joy than happy little bobbing TI logos. 
Up, of course. Is there any other choice? 
As much as I freakin’ adore the new Up skin, I just have to stick with WALL•E. That is like, my movie. Plus, I get to see the Up skin every time I browse the forums without logging in, so I get the best of both worlds!
little chef
The same one I always have, Monsters, Inc.. I’m stuck in my ways.
Whenever there is a new layout, I try it out for a week. But in the end, i always switch it with The Incredibles.
Cars…
Duh-chow! 
I decided to give the MI board style a try.
La Ratatouille, of course :]
^ urgh, I’ve really wanted to use that one for a while, but the bright red “BnL” bubbles that mark read or unread posts in the WALL•E board style stand out more to me and that’s why I haven’t changed it for a while.
But since I watched Ratatouille last night, and since you said that just now… man. I’m really tempted…
I give in. changes board style
little chef
Highfive!
Peer pressure… how dare you… xDD
jk, jk… I forgot how much I loved this board style. <3
little chef
Toy Story
Got me hooked into Pixar’s films, and, also, I keep using it 'cause it’s very bright and colourful.