Some more new brands I've tried:
Lion Sock-Ease: cheap and, well, nasty. This stuff's easily available at Michael's and it costs about $12 for a pair of socks. The colour palette is pretty limited and doesn't run into the "naturals" very far...no browns, greys, khaki, beige, only olive green...so right away it's not going to be a favourite of mine. The men in my family (and they are legion) are not going to put on a pair of hot pink socks. Maybe purple...Anyways, the yarn is rough and splitty (notwithstanding the aloe vera treatment they claim to give it), difficult to tink and frog. It's thinner than other sock wools I've tried and in fact a little on the thin side for 2mm for me! There's plenty of nylon in it though, and the ply is tight, so the wearability should be good.
Kroy 3-ply: this stuff is (unfortunately!!) discontinued, but I was given some from an inherited stash by a lady in my knitgroup. I've got enough for about 4 pairs of socks, in dark colours like charcoal, green, and blue. This stuff is most definitely thinner than most of what is available today. I've knit it on 1.75mm/US00 needles. The yarn is, in a word, FANTASTIC. Soft, with a fuzzy halo, it makes great men's socks. If it is anything like today's Kroy (4-ply) it'll last forever. I only wish it were still available!!!
Schoppel Zauberball: a European-style sock yarn (ie. thinner than what you generally find here in North America) with slow colour variations. No two balls are the same, and the colour shifts are unpredictable. Pick one of the wild "rainbow" colourways for some absolutely amazing faux-isle colourwork, or alternate balls with high-contrast for wild stripes. I LOVE this yarn. Too bad it is so expensive!!