Copic Questions

Hi! Sorry it's been over a week since I posted here last, I'll try to start doing better. I had a couple of questions for all of you who are experienced with the Copic Sketch Markers. I'm looking to buy a few more(I only have 3 right now) and I wondered if anyone had any recommendations of what colors I really need to have? I really enjoy coloring in the digi stamps from TGF and other places, as well as coloring in some traditional stamped images. I'm still learning how to best use the markers. I have a few Prismacolor ones, too, but I really prefer the feel of the Copics. The Copic colors I have thus far are: E00-Skin White, E49-Dark Bark, and Y21-Buttercup Yellow. I want to find a color that would be good for darker skin, such as for Jacob Black images.;) I also would like to find a good medium to dark blue for jeans and the like. Any suggestions would be appreciated, as I am thoroughly overwhelmed by the 300+ colors available. Thanks in advance!:)

-Laura