Regardless of how I choose to top, lettuce is huge no-no on burgers, or any other hot food for that matter. No nutritional value whatsoever AND slimy? No thanks. I also avoid it on almost all other sandwiches, FWIW, with the exception of Jersey Mike's cold subs. I'm weird that way, among many others.
If I had to choose one prep above all others I'd go with crumbled bleu cheese, bacon/onion jam, and a nice slice of beefsteak tomato. I prefer my patty on the rare side if I can get it.
Just looked up what used to be my fave restaurant version of said prep (Breakside Brewing in Portland, OR) and they've changed the recipe. BOO!
Have synthesizers, will travel...