These are a little more expensive than the ones listed above but you only need one skein/hank for a pair. I like Opal, Mountain Colors Bearfoot, and Tofutsies(be careful if anyone has seafood allergies). They range from 15-22 usually. Oh and add a vote for Lorna's laces as well.
Knitpicks Essential is also nice, very soft after washing and comfy to wear.