Gentlemen, choose your weapons.

http://en.wikipedia.org/wiki/Indent_style

I pick: Allman style.

Downside: Proprietary AIDS -
>This style is used by default in Microsoft Visual Studio 2005 and Apple's Xcode.

This is my usual style, it doesn't really follow a guideline in particular:

if (data != NULL && res > 0) {
if (!JS_DefineProperty(cx, o, "data", STRING_TO_JSVAL(
   JS_NewStringCopyN(cx, data, res)), NULL, NULL,
         JSPROP_ENUMERATE)) {
QUEUE_EXCEPTION("Internal error!"); goto err;
                       }
 PQfreemem(data); } else {
   if (!JS_DefineProperty(cx, o, "data", OBJECT_TO_JSVAL(NULL), NULL, NULL, JSPROP_ENUMERATE))
{ QUEUE_EXCEPTION("Internal error!");  goto err;

        }
            }