Wanting to start afresh..how do I archive?

Do a time machine back up then just copy back whatever you like.

 

OP wrote:
"I want a clean system install from scratch, then re-instate ONLY what I want & need."

Easiest way (you won't believe HOW easy until you try it):

1. Download CarbonCopyCloner from:
http://www.bombich.com/download.html
CCC is FREE to download, and it's FREE to use for the first 30 days.

2. Use CCC to create a BOOTABLE cloned backup on an external drive. It will be an exact copy of your internal drive and EVERYTHING will be there in "plain old finder format".

3. Boot from the cloned backup -- hold down option key at startup until startup manager appears.

4. Now, you can re-initialize the internal drive, and install a completely fresh copy of the OS onto it.

5. At the close of the install, you can use the setup manager (if you wish) to selectively migrate stuff from the backup drive.
OR
Create a new "empty" account, and then "selectively copy" from the backup to the new drive.

WARNING:
This will probably require that you "re-set up" some applications.

Also be advised that you can't just copy the main "sub-folders" from your OLD home folder into the NEW one.
Example: you CANNOT copy the "Pictures" folder from your old home folder to the new one, but, you CAN copy all the items -inside- the old Pictures folder, and paste them into the new one.

Also be advised that your best course of action will be to reboot from the NEW account, and set "get info" for the backup drive to "ignore ownership on this volume". Otherwise you may run into permissions problems after you copy over the files you want.

 

Yes and if you do a complete back up you can still just reinstall what you need and still have all the other stuff in case you made a mistake.

Then once you are sure you've got what you want just format the external drive and do a fresh backup, voila a clean system and a new backup to start fresh from.