What are you deciding, sashing? If this is for sashing, I must be odd man out. I think the blue does not play nicely with the blue in your blocks. If you really want your blocks to be the star and the sashing to be secondary I would go with the green (that looks brown in the picture) or the tan.

I like the blue

I vote for the tan

I love the blue, but then that is my favorite color. I do see how the tan would give it a southwestern look though.

The Blue - definitely!!

I like the blue.

tan...

blue.

i like the brown, maybe the tan. but i like how the brown brings out the lighter colored pieces. going to be so pretty

PURPLEPURPLEPURPLEPURPLEPURPLEPURPLEPURPLEPURPLE

Do you want to be safe or live outside the box a little!

Your blue blocks and the purple just sing together and takes tradtional blocks to a new level. :D
Peace