We use
Shutterfly for
Bob's photo business as well as our personal photos and the Scout troop. It's Mac compatible, easy to use, and has many useful functions for sizing images once they're uploaded and yes, I trust them to keep the images safe.
You can order hard-copy prints, CD's with images, photo books and lots more from the web site.
I've seen other pro web-hosting sites that I like better, but some aren't Mac compatible and others are just too expensive for the volume of business we do. Also, it's convenient to have all three sets of photos in the same place. I'm keeping an eye out for better options for the business photos, but I won't move the scout troop or our personal photos.