Another option is to save a complete image of your existing drive with a product like Ghost, see here:
http://www.symantec.com/home_homeoffice/produc ts/overview.jsp?pcid=br&pvid=ghost10
Then restore the Ghost image on to the new hard drive.
Ghost is clever enough to not care if the source hard drive was not the same size as the target hard drive.
The only problem you may have is where to store the Ghost image while you are removing the master drive.
I have a Master and a Slave hard drive.
I use Ghost to save the image of the Master on to the Slave drive.
Then I can restore the image from the Slave back to the Master.
Using this method I can "install" Windows XP from a Ghost image on the slave in about 5 minutes.