Don't get sucked into purchasing a bag that has Rick Steves name on it. That doesn't make it a better bag. I've seen the quality of the RS stuff, and it's not that great. The fabrics used by the company that makes this for RS are cheap, noisy. The seams are not that well sewn and the bags are just a "pocket" with straps.
you should really look around at local sporting goods stores, travel shops and outdoor stores. The outdoor stores will offer the best product and hopefully the staff's knowledge will help you pick the best pack for your use. I recommended the High Sierra brand since they are in the business of making day packs, know what they are doing and offer a great value- more pack for less money. Look for things like extra pockets, key fobs, internal organization (great for pens, lip balm, small notebook, snacks)
You are using it casually, just for the plane ride and day trips. Get a bag that has a padded back, and good curved shoulder straps to fit your shoulders for comfort. you should have several pockets to stay organized, and a water bottle pocket on the outside of the bag is very important to stay hydrated.
I highly recommend the following bag, and it's on sale at ebags http://www.ebags.com/product/high-sierra/opie-backpack/110400
From the looks of the Civita bag, it's made of micro fiber. That offers no stability. It's a sack with straps. you will feel everything you have in the pack on your back. It will sag with the weight of water/guide book, etc. By the end of the day, you will feel it in your shoulders. You mention you wanted something that will hold it's shape? This bag will not.
If you are looking at the Veloce, it's too large for your use.