You may still want to consider white or maybe dark grey or black. I agree that you can't expect a quick dropout in PS with chroma-key... in fact, you could have a problem with blue or green fringing from light bouncing off the backdrop. With a white outfit and the model standing on and/or fairly close to the paper I'm thinking the fringing would be pretty severe.
I cost myself a lot of time once shooting a guy on Chroma-key blue thinking exactly what you're thinking. I had light blue fringing in all kinds of places... between fingers, inside jacket cuffs, shoe tassles... 21 images, short deadline. It was murder.
After hundreds of background removals (did 71 cheerleaders once, I'll never see them the same way again), I like white paper lit one stop brighter than the subject. At two stops over, fringing starts to cause soft edges even with white.
I don't use the extract tool anymore but it's a good place to start. The pen (path) tool is the way to go once you get used to it but it's not exactly intuitive. You have to know it well to work quickly but it's very precise and you can do all kinds of tricks to shape and apply the selection once you have a path to work from. Plus, you can extract from practically any background without regard to color or complexity.
In this image, every component with color is bounded by a path... they get to be fun once you practice with 'em.