Why oh why the 80 character limit? It's the 21st century, screens are huge! I'm not saying let's put the limit in 300, but 100 or 120 is good enough to fit side by side diffs in one screen.
1 - yes, screens are huge, but it doesn't mean people can/will use small fonts or will scroll the screen
With today's big/wide screens it's more useful to have code side by side.
2 - Abuse. The 80 character limit is a pretty good indicator that you should be doing something else instead of having your code go over 80 characters.
Long lines are confusing, and you most likely can split the logic in several lines, facilitating maintenance.
I think having a soft and a hard limit makes more sense, if anything, I would make 80 characters the soft limit and perhaps 100 a hard limit, although I'd prefer them to be 100 and 120.
However, I've actually found it to be a good thing - I'm sure it aids readability.