Agree with just about everything mentioned above (version 2, gigabit, etc). But additional hint: if you are starting with larger new (i.e. empty) drive(s), an easy way to copy existing data is to use the built-in MIRROR function (it will be all local, fast & reliable). When finished, disable mirroring & pull out the old drive that was mirrored. This only works ONCE for each new drive you are planning to install, since mirroring overwrites the destination (your new blank large drive). But if you mirror the old drive with the largest amount of data on it, you'll at least have made some significant headway.
The suggestion about booting LiveCD: yes ! But you should also be able to do that on the NL hardware, no need to move the old drives to another PC. (And if you have just a little familiarity with Linux, you can copy data from the old drives to the new one(s) that way. And again it's local and should be fast.)
One word of
caution with this method: I am not sure about permissions / ownership of the resulting files copied to the new larger disk with LiveCD (someone else needs to help here ...)

Georg