Darth Lefty 

For cargo bike: get matching luggage. That's an easy one. That's the whole marketing pitch of the one you posted.

For regular bike: No matter what you get you will be able to work what you've got into your daily plan, or vice versa. I tend to like the tail bags with fold-out panniers. They have space for lunch and a change and can fold out for shopping on the way home. I've used them myself and was happy enough. But they are much smaller and they may not hold up as well as paperboy baskets or those big Ortleibs to daily fillings. Right now I'm in a kid hauling mode, taking truck to daycare then riding from there to work, and getting groceries is not really in the plan at all. So I'm using a backpack and only have little frame bags on my bike for the bike stuff.

I also see plenty of people riding with plastic grocery bags hung on their handlebars. But you probably won't find anyone on a bike forum to tell you it's a good idea. Here in California's elbow they lately implemented a 5cent bag law to encourage people to use totes. But ironically it's not expensive enough, and at the same time people don't want to get ripped off for their nickel, so they sell us plastic bags that are much sturdier than the old ones.