You want a sock that is mostly polyester. Avoid 100% cotton socks. In some brands, they'll call polyester "coolmax" or something like that.
Swiftwick makes great socks. So does Smartwool.
If you wear size 9.5 or smaller, Danskin makes a great ultrathin sock. It's a ladies sock, but it's white and a sock... that's about as unisex as you can get. Six pair cost $7. I wear these in summer and Swiftwick in the fall/winter.
Here's a link.
http://www.walmart.com/ip/Danskin-Ladies-Ultrathin-Lowcut-Socks-6-pair/46080703
Oh, and here's a tip. If you go with any of these choices, air dry your socks instead of putting them in the dryer. The heat will shrink them even if they're polyester.
Once you figure out what thickness you like, you don't need to pay a lot for socks. I found Fila low ankle polyester running socks 3 for $2.99 at TJ Maxx. I bought three and tried them out. They were great, so the next time I drove by TJ Maxx, I bought 12 more pair.