Bridgedale for me but they're a double edged sword as, yes they're expensive (£15 -£25 a pair) BUT they last years, and I mean like 5+ years easily and remain comfortable through-out that life-span. They mainly make multi-coloured hiking socks but about 3 years ago they started doing a selection of just plain black & dark blue socks (called liners) that can easily be described as "office style" socks and I use both types - thick green hiking socks at the weekend and these new black office style "liners" at work during the week.
As a negative however, the black ones however I find can be excessively "fluffy" when new meaning some black bits can left in-between your toes after wearing them.