A 3-pack of navy trouser sox should be easy to buy, fit well, stay up, and last.  Who has the time to search for such a basic wardrobe item?  I have always appreciated Gold Toe's colors, fit, and durability.  It was a no brainer for me to buy them, and they are just what I expected.  I appreciate also that they are opaque but thin, so they are comfortable with many types of shoe, from Tom's to business flats.