load_stuff.js

var files = ['file1','file2','file3' /*...*/];
var counter = 0;
var length = 0;

var afterLoad = function () { /* all our files are loaded in here :) */ }
for (var i = 0; i < files.length; i++) {
    //Increment length counter so we know that a request has been sent...
    length++;
    require('fs').readFile(files[i], function (data) {
        //Increment counter variable so we know where we are
        counter++;
        if ( counter >= length ) {
            afterLoad();
        }
    });
}