If Mexican = tacos and Italian = pizza to you, then I pity your taste buds and digestive system.
Both countries have vibrant cuisines that vary greatly by region and usually have nothing to do with the lowest common denominators mentioned above.
It’s been a long time – long enough that I have already forgotten where I put them – but I used to collect ethnic cookbooks back when I fancied myself an aspiring cook. Mostly Asian and Mediterranean, but I was amazed at how few Italian recipes were NOT pasta and did NOT have tomatoes in them. The closest to an authentic Italian eatery (not necessarily restaurant) I’ve found in this area had an abundance of non-pasta dishes. Some that I tried were spectacular. Of course, nowadays Italian is pizza and pasta – and cannoli! 
It does help if you like chile peppers, though. I don’t find any kind of Mexican particularly spicy (it’s kind of medium spicy on the cuisines of the world spicy scale. A fiesty arrabiata can get spicier than many Mexican dishes), but chile peppers do play a pretty prominent role, so if a little heat ain’t your thing, it can be a bit difficult to get into. Sure, plenty of stuff can be made without any kind of chile peppers at all (and plenty of dishes have nothing to do with chile peppers), but you’d be missing out on good bit. Like I said, I doubt there is a cuisine in the world that makes use of the various flavors and heat levels of different chiles better than Mexican cuisine. From the mild, deeply flavored, raisiny-pruney ancho, to the hauntingly smoky, spicy chipotle, to the sharp, earthy arbol, there’s just so many flavors and heat levels to choose from.
Hm, in that case, I look forward to someday trying those dishes.
And American food is characterized mostly by the use of exotic vegetables, such as maize and squash. No, of course they don’t seem exotic to you: That’s kind of the point.
It helps if you can find a place that specializes in Mexican seafood (which is going to be difficult for most people, I think). In my neighborhood, they are a dime a dozen, quite often across the street from each other. I have absolutely no idea how they survive with (what appears to me at least) the over-saturation of all these mariscos places.
I’ve never been to Mexico or Italy so I can’t comment on authentic cuisine from either location. I’ve stayed for extensive periods of time in texas and New Mexico and some time in Southern California. I also grew up in what I consider the best area for Italian American food (the NYC/NJ area, I know others will disagree) with an Italian mother. So I think I have had a decent variety of both. I like Mexican food. Maybe even love it. But I wouldn’t have it more than once a week. Once every other week would be fine. I have Italian food of one type or another at least several times a week. Italian is ahead by a wide margin. What I have had of Spanish food I have liked quite a bit. But it is pretty close to Italian.
If we are talking authentic, I would have to say Mexican. I like Italian food, wouldn’t pass it up if offered, but I’m never really craving it, except for maybe pizza or pepperoni rolls.
Oddly enough, being a small town in West Virginia we have some very good authentic Mexican and Italian eateries to choose from.
Mexican by a hair, I think, but that’s a really rough call to make.
Here in the penumbra of New York City, I can get spectacularly nice Italian cheaply in lots of nearby places; Mexican is thinner on the ground and fantastic Mexican kind of rare. More than there used to be, though.
Say, aren’t you the dude that just called people pretentious in another thread?
Anyway, who said anything about Mexican=tacos and Italian=pizza?
The guy who posted just below you and an hour later pretty strongly insinuated it, actually. But it was a general statement, not a specific condemnation of anyone’s post. Terribly sorry if I trod on your sensitive little toesies.
As for “pretentious”…it takes one to know one. That’s how I spotted the OP! 
Without considering desserts, I would take Mexican over Italian by a wide margin. In fact, two years ago the family spent 10 days in Italy (Rome/Tuscany/Cinque Terra) and the only Italian that really got me was made by a Chinese family. (Again, not considering desserts here.) I will say that Italian seafood is on the whole way better than Mexican seafood.
I wonder if quality Italian is more obtainable overall in the U.S. than is Mexican. A few years back I tried to find Mexican food in Seattle and the only Mexican food we could find put ham in its tostada.
Full disclosure: I’ve lived in L.A. all my life, so have been exposed to great Mexican food as the norm.
Apology accepted in the spirit it was made.
No doubt.
Actually, BigT said that he thought of Italian as mostly pasta, and that pizza he considered American.
Also:
What, this guy?
That was a joke, son.
Cite:
I got my first job in a family owned Italian restaurant. The matriarch of the family was still an active part in running the kitchen. When I was fourteen, I thought she was over a hundred years old, but she was probably in her seventies. She only spoke about a dozen words of English, but she made sure that every dish that left the kitchen was up to her standard. I learned a lot of what I know about cooking from this grand old lady. By age fifteen, I started out at the salad station and later moved to the pizza oven and then the cooking line.
I love Mexican food, but my kitchen palate is still mostly Italian.
Indianapolis and the surrounding metro area seems to be a magnet for hole-in-the-wall Mexican restaurants. Purportedly, they’re all money-laundering ops, but the food is always exceptional, so whatev. 
Nevertheless, I grew up next to a southern Italian family, so I know from Italian food. Mom and dad came over on the boat and mom was the best cook I’ve ever known.
To this day, I can still taste her homemade pasta dough. She would have to make extra for us kids, otherwise we’d steal her blind before the cooking could actually commence.
The problem is finding good Italian restaurants here. They are few and far between, unfortunately.
That is a very cruel decision to force someone to make. I loves me some Mexican food and could eat it 5 or 6 days a week, but Italian has more of a variety and you have great wines to go with it. On the other hand, a freshly made chimichanga with skirt steak and cheese was among the best things I’ve ever eaten.
<glares at JohnT> I will take Italian, sir, but I am not happy at all. :mad:
Italian, by miles. I live in a red sauce town and we have bakeries cranking out fantastic Italian bread. My own Italian cooking is about as good as it gets. The only Mexican food I’ve had is Taco Bell, and maybe a step up like Salsarita’s or Moe’s. I’m just not that fond of the same old chili, beans, cheese, tortillas, tacos. I find it boring. And I just KNOW there’s really good Mexican food out there, somewhere, but not where I live! Would love to give it a try.
Unless it’s a place I know that makes great chorizo and uses lots of cilantro, I go Italian.