I have used Gems Opal merino wool which is very soft and also machine washable and dryable. I've used it for other projects besides socks as well.
FO tally since knitting odyssey began in Jan. '05:
5 baby blankets; 2 afghans; 1 large afghan for large brother-in-law; 4 scarves; 4 toddler sweaters; 6 simple teddy bears; This teddy bear and 4 others from the book
; 1 monkey; 1 tank top/cardigan set; 1 cape; 1 shrug; 1 pair mittens; 2 pairs socks; 2 pairs felted clogs; 1 hat; lace edged tank
, Vitadini Lace Yoked Top
Currently working on: scarf for sis