Dual backup strategy for Macbook Pro 13"?

Looking for suggestions for a dual backup scenario I would like to put in place for my new Macbook Pro 13".

The first backup will be my Macbook Pro system and internal drive's files to External Hard Drive #1. I had planned to use Time Machine for this as this covers files I use on a daily basis. I think I'm good here.

The second backup process would be dropping files I rarely use but need stored, onto External Hard Drive #2. I would then need a backup/syncing option from External Hard Drive #2 to External Hard Drive #3 as there will no longer be a copy on the Macbook Pro itself.

My primary question is what to use for that Drive #2 to Drive # 3 Backup/Sync scenario. I'm looking for something I can run at will that will look at External Drive 2 and incrementally backup to Drive 3. Thoughts? Is there a simple, incremental, utility on the Macbook Pro that will accomplish this? Do I need to purchase something else...such as SuerDuper!...etc?

Any thoughts are greatly appreciated! Thanks!

CarbonCopyCloner

or SuperDuper.
It is worth noting as well, it would be recommended to do a clone of your HD with either SD or CCC, so you have a bootable clone just in case that your internal crashes.
TM is a good strategy but it dosent make a bootable clone, so you would be up the creek and without your work.

Just food for thought

Cheers

Here is how i do it - i have a Voyager Q and 2 1T HDs both partitioned identically with smaller of 2 partitions for Superduper.
One HD being kept off site. Then every week or so when visiting Sis in Law take recent back up HD and swap it for one off site.
Then prior to doing any changes back home, do a Smart Update - takes 6 - 8 mins on Firewire 800.

Thanks everyone!