PEP 8 : Maximum line Length :

[Gregory Ewing]

Ben Finney wrote:
> The 80 character line limit is *not* driven by a limitation of computer
> technology; it is driven by a limitation of human cognition. For that
> reason, it remains relevant until human cognition in the general reading
> population improves.

Another thing: Just because I may have 2048 pixes of
horizontal space available on my monitor, that doesn't
mean I want to devote all of them to displaying a
single source file.

I like to be able to put 2 or 3 source windows side
by side, or have a web browser showing documentation
alongside while I work, etc.

While the limit doesn't have to be exactly 80 chars,
something not too much bigger is a good idea for a
variety of reasons.

-- 
Greg