I always promote the use of semi-colons when writing Javascript. Often the interpreter will be able to infer them for you; but I have yet to see a reason (asides from laziness ;-)) why you would deliberately write your code in a less precise fashion than possible.
To my mind, if the structure of the code is obvious, it will be really clear where the semicolons go, such that you won't even have to think about it after getting in the habit (i.e. at the end of each line); on the other hand, if it's not immediately clear to you where the semicolon goes, then chances are the structure isn't the most obvious anyway, and explicit semicolons are needed there more than they would be elsewhere.
It also gets you into the habit of understanding and delimiting statements in your head, so you have a (admittedly marginally) better understanding of how your code might parse into an AST or similar. And that's got to be a good thing when debugging syntax errors.