For me it just depends on the situation. I always try to keep the horizontal scrollbar away, and that's with the editor using less than the complete screen width. And for multiple commands, it's always commands on new lines, except for some
while ($regex(%a,\w)) { inc %i | echo $regml(1) } oneliners

Oh, and the last example is bad coding

if ($blah) do this
if (blah) { do that }
if (test) {
one long or multiple commands
}
if (very long test) $&
some long command