Well, after having re-tiled 21 bathroom walls, I've set more than my fair share of wall tiles, but I have yet to set my first floor tile. So, I'm no expert on floor tiles at all. But, I'll tell you what little I know...
However, you should be aware that since floor tiles are individually set by hand, it's not at all uncommon to have slight variations in the tile height from one tile to the next. Most of the time you don't notice this height difference on a floor because it's small and the tiles LOOK like they're all at the same height. Your brain presumes they're all at the same height mostly just because of lack of visual evidence to the contrary. However, one of the most common problems using ceramic tiles for bathroom floors is the slight difference in height between individual tiles under the toilet which cause the toilet to "wobble" a bit. Tile setters will wedge coins (like pennies and dimes) under the base of the toilet bowl and then caulk around the base (to hide the coins) to prevent the toilet from wobbling and the customer from complaining.
If you look at a bag of thin set mortar, they will typically recommend a 1/4 inch square notched trowel for tiles smaller than 10 inches by 10 inches, and a 3/8 inch square notched trowel for larger tiles. The reason for the difference is to accomodate more of a variation in the floor height under a larger tile. That's the same as saying that the smaller the tile used, the more the tile floor will conform to the shape of the floor you're setting the tile over. Most people just aren't aware that floors often aren't flat, and that's mostly because the mind assumes floors are flat unless there's clear visual evidence to prove they aren't. I really don't know if wood or concrete floors tend to be better in that regard, but a concrete floor would always make a better base to tile over because of it's strength, rigidity and dimensional stability.
I don't see any problem using the same tile in different areas or rooms of your house. I think that would look better than using different tiles in different areas. But what's most important is to use a practical flooring in each room, according to the expected activity in that room. At the end of the day, that's always going to be more important than how the flooring looks in that room.
So, I think that it's fair to warn you about potential problems like this if you use any kind of ceramic tile or natural stone in your dining room or kitchen. You may find that you have to wedge something under one of the legs of your dining room table or kitchen stove to prevent it from wobbling a bit, although you'd expect the problem to be worse with a toilet because of it's smaller footprint and the fact that porcelain is so much more rigid than wood. (Also, normally the two front feet on stoves and fridges will be adjustable so you could always adjust the feet of these appliances to be stable regardless of a fluctuating floor height.) But, the normal variation from piece to piece in natural stone is only going to exacurbate this problem, tho. I'd suggest using natural stone in a front or back entrance way where you're going to be tracking in mud, salt, snow, etc. You need a strong durable flooring to stand up to road grit tracked in by footwear. If you do use a stone in your entrance ways, be sure to use a HARD material to stand up well. Ceramic floor tiles are rated according to their hardness with a "diamond number". The more diamonds, the harder the tile. Typically, the hardest tiles (called "porcelain tiles") will be rated at 5 diamonds. I've never seen a ceramic floor tile rated at anything less than 3 diamonds. Some natural stones, like marble are relatively soft and simply don't stand up well to abrasive stuff like road grit or sand on them. Walking on that sand or grit grinds the sand or grit into the relatively soft marble, and that results in the high traffic areas starting to show as "worn areas" on the marble floor. I'd suggest using granite if you opt for a natural stone, and the hardest ceramic tile you can find (that still won't be slippery when wet) if you opt for a tile.
If you do use a natural stone or ceramic tile in your kitchen and/or dining room, then you would do well to "seal" the stone, tile or grout lines. There are two kinds of grout sealers; those that penetrate into the grout and those that form a film over the grout. In a shower, then the penetrating grout sealers are a better choice because the grout protects the sealer from getting worn off or eroded by the shower water spray. However, in a kitchen counter top, kitchen or dining room floor, it makes more sense to use a film forming sealer. That's because penetrating sealers won't plug the porosity of the grout, and so soft foods like peanut butter can get mooshed into the porous surface of floor tile grout, where they can provide a food source for bacteria and even bugs. On kitchen floor or counter top grout, I'd use a film forming sealer rather than a penetrating grout sealer.
Also, there are two kinds of film forming grout sealers; silicone based and acrylic. The problem with all silicone based grout sealers is that nothing sticks well to them, not even silicone based grout sealers. So, if after 20 years, you find that the silicone grout sealer on your floor or counter top grout is wearing off or wearing thin, then you can't really add another coat because that new coat won't stick well to the stuff that's already on the grout. Acrylic film forming grout sealers don't have that problem. They're exactly like latex paint in that each coat adheres to an underlying coat as well as the original coat adhered to the grout. There's a company in California called Glaze 'N Seal that makes a general purpose acrylic film forming grout sealer that I'm using in my bathrooms that seems to be very durable. It's just called "Grout Sealer".
Take a look at the product data sheet for this sealer. I imported 4 quarts of it from California to Canada, and so far I like it a lot.
Another option you probably haven't considered for the entrance areas would be synthetic rubber flooring. Synthetic rubber is one of the most durable flooring choices I know of. I have synthetic rubber stair treads in both the front and back stairwells of my apartment block, and the stuff is bullet proof. You cannot harm this flooring with anything duller than a razor or cooler than a torch. Synthetic rubber flooring is the only flooring I know of that's used in golf shops and skating rinks where people walk on the flooring with ice skates and spiked shoes. Also, nothing beats the coefficient of friction between a rubber soled sneaker and rubber flooring, and synthetic rubber flooring is available with a textured surface for use in wet areas. Johnsonite is the biggest name in synthetic rubber flooring by far, so why not spend an evening at www.johnsonite.com
to see what's available in synthetic rubber. Be aware, however, that synthetic rubber flooring is not inexpensive.
A practical option for your kitchen would be a strong natural linoleum (like Marmoleum) that would be strong enough to allow you to move the fridge and stove out without tearing the flooring. Marmoleum would be a practical flooring for a dining room, too.
Maybe keep in mind that you're only going to LIKE the look of your floor when it's brand new. Before long, you're going to take the floor for granted, just like you take the styling and colour of your car for granted now. When's the last time you looked at your car for any reason other than to find out where it was. So, as you become used to the appearance of your floor just as you've become used to the appearance of your car, what's going to become progressively more important is how suitable the flooring is to the activity in the room it's being used in. A natural stone floor might look great in your dining room when it's new, but if you find you have to wedge something under one leg to stop the table from wobbling, that's going to get real old real fast. So, pick your flooring with practical considerations in mind. You're going to get used to the look of the flooring within a year or two, but you'll have to live with it for a lot longer than that.