Node.js Tools for Visual Studio includes intellisense support based upon Visual Studio’s
XML documentation comments, and
or require('fs') or other packages.
Node.js also models the packages which are within your project (the modules need to be in your project, not just on disk). For example if you install express into node_modules you'll automatically get completions against the express object model.
Likewise as you develop your own packages within your project you'll get intellisense via require through the various packages.
Alpha bug note: Currently for large projects with lots of packages intellisense will sometimes stop working part way through a file. This is dependent upon how many requires are used and how many other packages the required packages require as well
as the speed of your computer.