My personal preference is this:

    var assets = "/images"

    var sounds = assets+"/sounds"

I always use relative paths with a leading slash (`/images/...`), it feels less prone to error, to me.  It is also more fool proof to use `var sounds = assets+"/sounds"` because even if `assets` had a trailing slash and you ended up with `/images//sounds`, it would still resolve to `/images/sounds`.  The one disclaimer being that it depends on your request handler.  Apache seems to handle it fine (at least certain versions/configurations, see http://www.amazon.com//gp//site-directory//ref=nav_sad).  With the other way you'd end up with `/imagessounds`, not so fool proof :)  There is also the option of checking for double slashes and cleaning them up.  Not an option with the other approach.