Personally, I like doing all the declarations on their own line as well. But anytime I've used JSLint in the past, I seem to recall it complaining about that. Perhaps I'm mistaken?
That feels like a situation that could easily end up (copy pasting something, someone adding another var, ...) in an unexpected global variable declaration.
var foo = 4,
bar = 5,
baz = 6,
sprinkles = 'wee';
qux = 'quux';