Pizza: Due; Gino's East (Chicago). Chicago-style pizza is the best!
Italian: The Italian Village (Chicago). Food's good, not exceptional, but the ambience is great, especially upstairs, which is designed to look like, well, an italian village. Great spot for a date, I have observed.
Tex/Mex: Frontera Grill (Chicago); Tacos del Lago (Evanston, IL). Frontera is owned by renowned chef Rick Bayless and is exquisite. Tacos del Lago is a great little place in Evanston to which my girlfriend introduced me; it looks kind of sketchy (at least by Evanston standards) on the outside, but it is really fantastic.
Malaysian: Bentara (New Haven, CT). Ate here with a friend when I visited New Haven and it was delicious. But this is probably an unfair pick, since I don't have much experience with Malaysian food.
Coffee: Italian Coffee Bar (Chicago). Wow, this is great coffee and better yet, really great employees. I love going to the one near me, though there are a few other locations under Chicago. And these folks are really serious about their coffee, experimenting with new things and entering in competitions and such.
Indian: Woodlands (Chicago; Charlotte, NC, also, I think, and a couple of other locations). Woodlands is either an extension or a rip-off of the Mysore Woodlands restaurants in Karnataka, India. It's just great vegetarian, South Indian food, and has a number of locations around the country. Chicago is pretty well known for Indian food (Devon Ave. is legendary amongst South Asian Americans) and I think Woodlands is at or near the top of the list of Chicago's Indian restaurants.
Sandwiches: Eppy's Deli (Chicago). OK, this is just one of those "you've got to be here" things. Eppy's has great food at a remarkably cheap price for downtown Chicago and when you go in, there is a whiteboard with messages dissing their competitors. The owner is this guy who describes himself as "an *******" and is hilarious.