There are lots of good brown egg layers. looking for quantity or quality? For personality I would strongly, strongly recommend an orpington who lays medium sized brown eggs, My Plymouth Rock has a no nonsense attitude though, but lays huge brown eggs regularly, but is realy noisey and sort of mean to the others. My RIR, lays frequently, but medium brown eggs and is nosey and skittish. I only have three chickens though so I wouldnt know about other breeds so hope-full someone with more chicken experiance will pipe in!
You would probably get lots of great answers if you put your question in your title.
I have found my buff orps are great brown egg layers. RIR and Black Australorps are notorious for excellent brown eggs as well. If you're looking for super dark eggs, Welsummers and Marans may fit the bill, however I do not know how well they lay.