It's usually beef or chicken with me and sometimes turkey. I think grilled, skinless chicken breast has the highest protein/calorie ratio so it's definitely the healthiest but you can't match the taste of a good piece of steak. And ground turkey is no match for ground beef in your spaghetti sauce.
Usually it's a combination of cottage cheese and yogurt, with some chicken or fish added in here and there.
While things like steak and pork chops taste good I eat something like that maybe a couple times a year. I find I don't miss them as much as I thought I would.
I've been roasting a lot of pig over the last few months, versatile, takes other flavors well, and cheap. I don't have a favorite but pork has become my staple protein source.
I like seafood such as shrimp and fish, but avoid it due to concerns about mercury contamination and biological build-up of heavy metals.
For what I do eat, I like whole almonds with Tamari soy sauce, chocolate almond milk, beef tacos and chicken quesadillas with spicy pinto beans, and more.