The spinach is more for color than anything. I don’t care either way. But your paprika comment reminds me I like a little bit of nutmeg in my bechamel layers, too.
I am happy with all/any of the above. Variety is the spice and all that.
I like a primavera sauce for the ‘meat’ layers, and a ricotta/parmesan/steamed spinach combo for the ‘cheese’ layer, with a liberal application of various cheeses on the top (Kraft Italiano mix is great - parm, mozza, provolone & emental).
Smoked duck is amazing in a white lasagne, although I must admit it was more like the world’s best mac&cheese than like a lasagne to me. In my tiny brain, lasagne really needs to have a tomato based sauce to be a proper lasagne.
Spinach is weird in lasagne. It’s limp and I can’t really taste it so it’s just winds up being a slimy texture nightmare or it goes unnoticed. Either way, I don’t understand spinach lasagne.
I like my lasagna the same way I like my '70s TV shows: the cheesier the better. 
I want to make a vegetable lasagna and I pore through recipe after recipe, but I’m afraid it’s never going to be as good as Stouffer’s Vegetable Lasagna…I used to make lasagna every Christmas Eve, very simple, noodles, ricotta beaten with egg and oregano, sauce, drained cooked italian hot sausage, grated mozzarella…always came out a bit dry, so we had a pan of sauce to pour over if needed. I think I’ll make it this year too, what the heck.
I’ve had some good vegetarian lasagna, but it had better be tomato-based (I don’t really like white sauces on anything). But I like meat in mine.
I love the Atkins lasagnas made with big pepperoni slices instead of the noodles. Ground beef and Italian sausage in the sauce, with lots of cheese and spinach. Mmmm!
I have boasted about this before, but I made lasagne for my Italian (as in, from Italy) girlfriend that hade her eyes widen and her whisper “oh Jim…!”
The ground steak/onion ragout (put three garlic cloves in the oil before you brown the beef but remove the cloves before making the sauce) is made by boiling off a cup of milk and a cup of red wine before adding the tomatoes, fresh ground black pepper and oregano. From the bottom up: lasagne sheet, meat, layer of fresh basil leaves, lasagne sheet, béchamel, meat, basil, sheet, béchamel, repeat right up to the top. For the top layer you take the last of the béchamel and load it up with a huge amount of freshly grated parmigiano before spreading it. Bake 1 hour on a moderate heat. The last 15 minutes top with thin slices of balled buffalo mozzarella and scatter with oiled basil leaves.
I voted “other”. My SIL loves to make lasagna for all family events because she does it well, or so I am told. I am a celiac. I have to bring my own food. I once got even by bringing my own awesome, gluten-free, pesto pizza and forcing them to sniff the ingredients, but not allowing them to have any.
I have yet to find gluten-free lasagna noodles that aren’t gluey.