For me, it's grass-fed beef hands down. Any cut. Smothered in salsa. Oh yum. Close seconds are pork and salmon. Then chicken, lamb, tuna, shrimp and turkey.
The cow comes up as number 1 for me. So versatile, I can easily cook up some ground beef or a steak (rib-eye), but also enjoy some tougher cuts in a stew or beef curry. Beef liver pate. Not to mention the wonderful things cows secrete - cream and butter. I can't enjoy my day without a creamy coffee.
Then comes lamb. Tender and fatty, with spices like cumin.
3rd is salmon in various forms (sauteed, poached, baked, raw sashimi)...
If I could have an animal made of different types of red meat - lamb shoulder, beef rump, kangaroo legs, ostrich body, whatever - I would give up city living and start raising that on a farm so I could eat it all. It's too hard to choose between all of them.