In this radio broadcast Scott Hanselman talks to VsVim creator Jared Parsons. I use VsVim all the time, and would find it difficult to use Visual Studio without it.
For those die hard UNIX/Linux fans, it is nice to have good old VI mode right in Visual Studio and you don't have to lift your hand from the keyboard, just like you were always used to doing on Solaris, AIX, etc.,.
So once you have downloaded Visual Studio, as befits your situation, you can download the VsVim extension from the below link and extend Visual Studio to support vi mode. .
Why should you use VsVim from within VS, rather than a plain Cygwin build of VI. Well VS has many other features such as rock solid IntelliSense, integrated debugging with Intellitrace etc.,. which you will not get with other source code editors. This in essence is taking advantage of the best of both worlds. Note that for those not wanting to pay a dime to Microsoft, there is now the free Community edition of Visual Studio which is totally free for you to download and use.