Choosing soft boxes

I have three speed lights, SB900, SB800, and a SB600 and also have three Flex5, one TT1, and an AC3 pocket wizard controller. I also have three light stands with umbrella brackets. My question is that I am interested in getting some soft boxes and would like some suggestions on which ones to consider getting.

I own a couple Photoflex box's of diff sizes. Nice softbox. Not the cheapest, not the most expensive. Also own a couple Impact Quickbox's. Like those as well. When in doubt read the reviews. I don't buy anything without doing so.

The rapid soft box by wescott ..26 inch.. Or the new rapidbox duo which takes 2 speed lights and is 36 inch I believe... By wescott as well..