Since you are in TX and could go anywhere, a North American guide is essential. Sibley is by far my favorite. It's a bit larger than the others but it has the maps and everything all in one place. Sibley is an artist and painted every "plate" by hand. The paintings are more reliable that photo-based guides though each has its pros and cons.
For me this is the easiest answer in the world - Sibley. I do have Kaufman, National Geo and a few others but Sibley is the best. Those phone apps are a great supplement but not the primary source. I have those too.