This is a topic that is always rather subjective, AD
In-Place Migrations… One of my colleagues [Rick Claus] has been blogging about his experience over the years with just this
sort of thing: http://blogs.technet.com/rclaus/archive/2005/08/29/409948.aspx
When looking at the migrations, there are often many
questions you will be asking yourself and tasks you will be performing, from identifying
what you have now and where you would like to be, to looking at logical and
physical design components for AD. Whenever I have done migrations, one of the
biggest challenges is often just getting everyone’s buy in!
Rick has done a great job in a series of articles
give the benefit of his years of experience doing this for other companies
large and small. I would suggest taking a look if you are either planning a
migration or have already done so. He has a host of tips for you.
Oh, and please give him your feedback J