Backup software with a 'disaster recovery' mode usually allows this, I think Dantz retrospect does it, possibly Nero. You do a backup to a bootable CD/DVD with volumes for the data, remove the old disk, plug in the new one, boot off the bootable CD to format the drive then just plug the backup discs back in.
You can play around because at least you know you have the ultimate backup - your original hard disk! Buying good backup software is an excellent investment.
Be cautious over the new drive - my Thinkpad T40 firmware won't boot off non-IBM primary hard drives (although it used to until a firmware update usefully removed that functionality!)
BW