I like Sibley a lot, too, but I also have a soft spot for the Stokes guides because they have photos and not illustrations, and I always found the photos easier to use to ID.
The Merlin app is great. I also like the Audubon Bird app, because it has a great search feature where you can put in the location, colors, size, etc of a bird you don't know and it will come up with a list of things it could be.
For raptors, I LOVE the Crossley ID Guide because it has dozens of photos of each raptor from different angles and distances, both in flight and sitting. It's perfect for a beginner at raptor ID.
I'd also recommend Merlin, which is a free app and excellent all-around field guide, and if you want a specific raptor book, the Crossley ID Guide is a neat one.
This is the guide I use. I think it might be my favorite bird guide.