Um?
Well its a brand new hard drive. So you would install your OS from the CD/DVD... and you would Download all your programs again or wahtever.... and you would have to back up all your data like docs/pix/music onto like an external hard drive or something first.
Actually, this seems like the best and easiest option, using Disk Utility:
Duplicating a disk
You can duplicate one hard disk or volume onto another. For example, you
can duplicate a disk that contains photos and movies to send to a friend, or
you can duplicate your startup volume to use as a backup.
To duplicate a disk:
Click the disk or volume you want to duplicate and click the Restore tab.
Drag the disk or volume you want to copy to the Source field.
You can drag it from the list at the left or from the Finder.
Drag the disk or volume that will contain the copy to the Destination field.
If you can’t drag a particular disk or volume to that field, you can’t copy to
it. If it’s your startup disk or volume, start up your computer with another
disk, such as your Mac OS X install disk. Otherwise, try to quit any
applications that are on it or that use documents on that disk.
If you want to erase the destination before copying to it, select “Erase
destination.” If you want to use the copy as a startup disk, select “Erase
destination.”
If you want to add the original’s contents to the destination without erasing
it, deselect “Erase destination.”
Click the Restore button.