Universal JavaScript Module, supports AMD (RequireJS), Node.js, and the browser.

universal-module.js

(function(def){
def('myModule', ['someDependency', 'somethingElse'], function(someDependency, somethingElse){

    //return the module's API
    return {};

});
}(
    // wrapper to run code everywhere
    typeof define === 'function' && define.amd?
        //AMD
        function(name, deps, factory){
            define(deps, factory); //registering as an unnamed module, more flexible and match CommonJS
        } :
        (typeof require === 'function' && typeof module !== 'undefined' && module.exports ?
            //CommonJS
            function(deps, factory){
                module.exports = factory.apply(this, deps.map(require));
            } :
            //Browser (regular script tag)
            function(name, deps, factory){
                var d, i = 0, global = this, old = global[name], mod;
                while(d = deps[i]){
                    deps[i++] = this[d];
                }
                global[name] = mod = factory.apply(global, deps);
                mod.noConflict = function(){
                    global[name] = old;
                    return mod;
                };
            }
        )
));

usage.js

// AMD
require(['myModule'], function (myModule){
  // use myModule here
});

// Node.js
var myModule = require('myModule');

// Global
myModule
// if myModule is already defined, `noConflict` gives it back
var myNonConflictingModule = myModule.noConflict();

I like how your boilerplate is on the bottom and the module definition at the top.

imho even define && define.amd is safe enough. Doesn't hurt to do the additional check though.

in case someone reaches this gist, I just published a new post explaining why AMD rocks: http://blog.millermedeiros.com/2011/09/amd-is-better-for-the-web-than-commonjs-modules/