Personally I like my code to be no longer than 60 characters (that's because so I can comfortably split my Vim screen and view two files side by side).
When I am coding rails it often happens that I need to create some error message or user feedback and these strings get far longer than 60 characters normally. Until now I've split my lines using + in these cases.

print "This is a nice, long string giving you some " +
    "feedback. Unfortunately it does not fit on the " +
    "screen so I have to split it."

I dislike that syntax because it is a lot of hassle to get the spaces and the quotes right. There seem to be a few better syntaxes (according to this StackOverflow Question), but they do not substantially improve the situation I think:

print "This is a nice, long string giving you some "\
      "feedback. Unfortunately it does not fit on the "\
      "screen so I have to split it."

The solution I came up with was a little helper function:

# Helper for multi line strings:
# Normalizes the string, so that every sequence of spaces is
# replaced by a single space.
# This also strips the string.
def NOCR(s)
  s.gsub!(/\s\s*/, ' ')
  s.strip!
  s
end

print NOCR "This is a nice, long string giving you some
    feedback. Unfortunately it does not fit on the screen
    screen so I have to split it."

This is still not a perfect solution, but it at least saves me the hassle of manually formatting the spaces and adding lots of quotes.

Of course, when using this, support for inserting newlines or tabs is completely gone. It would be possible to use some kind of escape syntax (%%, %n, %t, %s) to introduce it again, but I think in these cases it is better to fall back to manual formatting.