If you use Lion Wool or Cascade 220, you'll have very thick, handwash only socks. Worsted weight yarn tends to make socks you wouldn't want to wear in shoes (I've done it before because they're WARM, but you can feel all the purl bumps on your feet). They'd be good for wearing around the house socks (I loooove mine!).
I second the Knit Picks suggestion. I think all of their sock yarns are fingering weight (I forgot if Parade is gone or not). If you're looking for something thicker, you could get a sport weight yarn. The smaller the gauge of your knitting, the less likely you'll be to feel the purl bumps on your feet, so if that bothers you, that's something to consider.
Whatever yarn you choose, have fun with it! Sock knitting is awesome.