Best way to copy Linux from one drive to another

[mheyes@lincolnfp.com]

What is the best way to copy my Debian installation from one disk to another?

I am trying to do transfer my current install from a smaller drive to a larger
one. I installed, partitioned and formatted the new drive with the same
partitions as the smaller one. Then, I copied each partition in turn (/, /root,
/home, /opt, /var, /usr) to the appropriate partition on the new drive with cp
-a small-drive-partition /mnt/new-drive-partition.

When I boot (from floppy) to the new drive, I am told that /var/lock,
/var/run/utmp don't exist. urandom start: fails. Then, when system switches to
run level 2, syslogd hangs. But, all the /var files and directories did get
copied.

Is there a problem with my approach, and a better way to do this?

Thanks in advance.

mike