For me, it's a full English including black pudding, beans, grilled fresh tomato, bacon, poached eggs, hash browns, large mushrooms, and freshly sliced doorsteps of toast with butter.
In second place comes eggs benedict but the eggs have to be perfectly poached.
I love a Sunday roast eaten out, preferably rare beef with Yorkshire pud and hot horseradish sauce, carrot and swede mash, roast potatoes, roast parsnips, sprouts, cauli, broccoli, cabbage, peas, and lashings of tasty gravy. Some carvery roasts can be acceptable, some can be totally dire. I prefer a gastro pub type Sunday roast. Roast lamb would be a second choice, pork third. Wouldn't choose chicken because we eat a lot of it at home.
I rarely/never do a proper roast for just the two of us so to have one cooked for me..a meal I love..is a real treat.