A guy needs three types of socks: dress socks, casual socks, and athletic socks.

Dress and casual socks, like ties, don't have to be a bland solid color. We're not talking argyle, but a pattern with some low-key colors can add panache to what you're wearing.

Your socks should contain minimal man-made materials (20% or less). You do need a bit to add cushioning, aid in moisture absorption, provide durability, and give structure to a sock, but too high a proportion and your feet can't breathe.

Wool, cotton, silk or blends of the three are great choices.  Cashmere is particularly nice, if you're loaded.

Going sockless makes your feet sweaty and your shoes smell bad. Unless they're sandals, wear socks.

There are three guidelines to follow with socks:

Socks should match up with your pants, not your shoes. This is something a lot of guys mess up. For example, with khakis and brown shoes, you should go for socks with some tan in them as opposed to an all brown pair (you'll look like you have a club foot otherwise). For a navy suit and black shoes, opt for navy-based socks as opposed to black. If in doubt, go darker.

With jeans, your socks don't have to match your pants.  In fact, a good pair of ragg or darker-colored cotton socks look fine with jeans.  Just stay away from the tube sock and jean look.  That just smacks of "Hi, I really dig looking like a tourist!"

We recommend over-the-calf dress socks that are to avoid a shameful condition called "Businessman's Leg," (just LOOK at David' shin above!  Foul!) where part of your leg is exposed when because your socks aren't high enough to cover you up.

Proportion matters with your socks, too. Wear thinner, finer dress socks with a suit and thicker socks with more casual things like jeans or cargo pants.