I was thinking the same thing. White seems to pull the whole thing together.

I would balance a few more light colors in the bottom half of your quilt as in the upper half. The white background does indeed make the pattern look like it is "floating"! Will be beautiful when completed!!!

Love the lay-out as is! But I think the setting triangles should be white. Then a small white border to "float" the center, or if your triangles are just a bit large, you can cut them one half inch from the tips to float the insides. Next, some scrappy borders. Piano keys, small squares set into white, the sky is the limit.

White for sure. IMHO anything else would detract from your design.

A nice medium gray will allow the bright blocks to be highlighted.

I like bjchad's idea of making more blocks and fitting them in the spaces. Then just add a narrow border and bind. You could possibly even do without a border.

I would place several different colors in the triangle areas on the board. Every time you walk in room, note which one you are drawn to first. That is usually the one you really want (but just don't know yet!). When someone is having trouble picking between 2 different fabrics, I ask them which one they keep touching. That is the one they want.

I personally like the white of your design wall for the triangles, as there is white in the blocks and your design wall looks good with white for a background.

I'm with Paper Princess.

I agree with 'paperprincess', the white looks good to me. Then use a bold color for the border.