I completely agree with everyone...you'll need them all. :knitting: In fact, if you're like me, you'll need duplicates of all the sizes, so that you can knit two things at the same time (2 socks, 2 sleeves, etc.).
I've learned both the Magic Loop and knitting with 2 circulars, but I still love knitting with DPNs the best.
Save yourself the time and aggravation...buy the entire set now. :roflhard: