battery grip will hold 2 batteries, thus giving you more life on your cam.
i have the lowepro slingshot. it's small enough that it's not bulky and heavy, yet roomy enough to hold my cam + grip + lens, 2 additional lenses, 1 speedlight, batteries, lens cleaner and
generic flash trigger.
http://www.amazon.com/Lowepro-SlingS...9736312&sr=1-5
afaik, office pic mgr is for viewing and sorting pics, but you can add watermarks using paint.