Crisp white well tailored top.  I usually purchase a medium in this style of shirt but based on reviews I went one size up to a large and the shirt fits well.  I would suggest one size up if you like a little breathing room.  I wanted a professional look.  If you wanted a tighter look or won't button the shirt a medium might have been ok.  Crisp feel to the shirt also emphasizes the professional look you can get with this basic fashion staple.