Shakespeare's an easy one, since he happily broke anything we consider a grammatical rule.

Here's t'other side of the coin, Shanks, in a NY Times review of "Doing our own thing" by linguist John McWhorter:
http://www.nytimes.com/2003/11/16/books/review/16CALDWET.html

Extract:
At some point in the 1960's, Americans lost faith in their written language, and settled for reproducing a less demanding (but more ''real'') oral variant on the page and in public. The result, McWhorter asserts, has been a steep and steady decline in the quality of political oratory, poetry, musical theater, preaching and -- ultimately -- thinking.