I've realised the difference between you and me: I don't use the storage exploit where everything goes down on the same tile (quantum stockpiles). Never seen the point, when storage can be beautiful and spread out. Room costs nothing, and even a 1x1 embark has practically endless vertical space, and a lot of room to spread out laterally.
I make my standard bedrooms at least 3x3, often to 3x6. Space is cheap, and makes dorfs happy, so why skimp? Nobles get much larger bedrooms (5x8 is often a nice size), with smoothed and engraved walls and elaborate statues and artworks. That said, sometimes I just have beds dotted about everywhere, and no assigned rooms. Well, not none at all: nobles who request them get private bedrooms, and the non-nobles can go sleep where they feel the need. Depends on the fort.
Tombs are about the same size as the bedroom, noble and military tombs larger, etc. If the dorfs have no bedroom, I try to make sure they have a chest and a cabinet in their tomb. No tomb smaller than about 4x4 if I'm doing it this way. That said, a graveyard is just a big room with lots of coffins constructed in it. The reason I do the tomb thing is because of my no-bedroom experimentation.
Food storage? I usually have at least three 10x10 food storage rooms to each kitchen. Often more. Seperate rooms for booze. The closest one I fill with food I want the kitchen to cook first. I have a seperate food storage and kitchen area for the butchers and tanners, restricted to fat, tallow and lye, so that I can make soap easily. This needs ash to be made, so a seperate log room (50x50 if I can get away with it, in case the elves want me to stop logging) and woodburning furnaces and so on. Often I put a bed in each food storage room. When !fun! starts going down, I can lock the doors on the sleeping dorfs, and leave them trapped with a few years worth of food.
Wellroom is a meeting hall, and thuswise usually at least 10x10, as it can be full of statues, art, a waterfall falling onto a statue and draining through the floor, some spare beds, and then a seperate room to the side with binless soap storage (if you use bins for soap, you get the weirdest cancellation spam). Often the wellroom has a minibar, or a zoo of chained animals around a pedestal with an unused artifact, or even a gaol area with private wells for the criminals to drink from. Often it has been smoothed and carved and even floored in imported brick tile. Sometimes it's two storeys high. You can't get too elaborate for a wellroom, it's a leisure area of the fort.
Hospital is usually about the size of the wellroom, with a private well, often sharing the cistern with the main meeting halls. Perhaps 8x12? If the dorfs like it there, they're less likely to let their friend die of thirst. Put in some bucket storage.
The Guildhalls need to be big and full of things or they won't be expensive enough. 10x10 again works for me. Smoothed and carved walls, artworks and statues, even another waterfall (I'm big on waterfalls).
My garbage disposal is usually a whole level, multiple 5x12 rooms. It adjoins an area for bonecarving and decorating with shell and bone. I also have similar rooms full of binless gemstones and jewellers stations. I don't usually bother too much with atom smashing until the fort is at least 10 or older. Perhaps that's my downfall, but it works for me.
When you first put in the Library (recommend within the first two years, but you can go later) it will literally fill with dwarves, as they all want to read a book. Count your population, and put in tables and chairs for anywhere between a third and a half of the population, and they should cope. They will definitely fill those seats. It doesn't need more than a couple of bookcases and chests though. So again, like the wellroom, it is a large and leisurely area, with chained animals keeping a close eye on the books so they don't get stolen.
Unless you are trying for some sort of bare minimum challenge, lavish large rooms and chambers and wide hallways will keep your dorfs from trying to kill each other in frustration.