Out of curiosity...
As a DM or even as a player...
What level of magic do you like in your D&D campaigns? How "much" magic? What place does it have in the world due to its lack or abundance? To elaborate on that, I've made a few categories which I believe help point out the most common types of approaches to magic (and the ammount of it) in D&D games, and medieval fantasy in general. They're as follow:
1- Mysterious. Magic is a mystery to people in that world. Some know for a fact it exists, some doubt it, some believe in it just as they believe other rumors without real proof. Or else maybe magic isn't all that unheard of by the population, but access to it is so restricted that only a handful in the world can actually use it. These settings usually spawn very few magical items too. Magic-wielders are usually mysterious characters and the nature of magic isn't there so much to be explained, but more to cause wonder and remain at least partially a mystery. A good example of one such setting would be Game of Thrones; and some versions of Arthurian legends, where you have maybe only Merlin and Morgana as mages, and only Excalibur as a magical item.
2- Uncommon. Magic is out there. There are wizards and magical stuff. People know that for a fact, but not many have had contact with magic or have necessarily ever seen anything magical. Magic in these settings tend to have a place of their own in the story of the world, usually not very much involved in the main social/political development of the world--which is in the hands of the warrior and/or noble class, much like in our real medieval times. Wizards and witches usually have their own orders, or are lone students of the arcane arts, or else maybe are counselors to kings but not kings themselves, etc. Whenever they do take part in government and politics it's usually some unique case or exception, or a limiting factor exists like in Dark Sun where only a handful of the world's rulers are allowed to even practice magic. Dragonlance can probably fit in here (by the age of the original books at least); so could Lord of the Rings, where you do see a lot magic but most of it is either in the grasp of a few, or is something natural, expontaneous and unexplained like the magic of the elves (arguably LOTR could fit into the next category too, I guess, but I think it's the main story in the books that focus more on the magical aspects, not a widespread use of magic in all Middle-Earth as a setting-thing); Dark Sun is another example, where magic is a fact and people live under the constant fear of their tyranical Sorcerer-Kings, but it is, however, mostly banned, forbidden, tightly controlled by the Athas's powerful rulers, and therefore not so much an everyday-thing for everyone.
3- Common. There is magic, everyone knows, and probably everyone has seen or wielded something magical at some point in their lives. Depending on where you live and who you are, seeing and experiencing magic (even if not wielding it) isn't really something fantastical but something expected or common. Wizards are a rather common sight, at least in populated centers, and there are probably magic schools where students can enroll, and magic shops where any man with enough coins can get some magical gear. Magic-users have a high chance of being part of the social hierarchy as an established thing, and maybe Kings and Governor themselves are wizards. Still, magic isn't for everyone, and the whole of society does not revolve around magic. It is there but it is still a thing of its own. Forgotten Realms is probably the best example of this kind of setting.
4- Everyday Thing. Magic is everywhere. Not only that, it is an everyday thing much like electricity is for us today in the real world. In a given city, at least a good part of the infastructure is powered by magic, and people rely and depend on magic even for their everyday lives. Usually in such settings magic is very much like science, at the grasp of almost anyone willing to understand it and wield it. Eberron is an example of one such setting, where cities have magical floating houses, magic-powered devices, and magical living golems are a common everyday thing to see. Spelljammer is another example, not a "world" per se, but the whole setting revolves around the idea of magical gears built and controlled more or less as a science, which allow people to travel in space where even more calculated-magic is needed for survival and exploration.
I'm probably more of a 1-Mysterious kind of guy. I just love that kind of fiction, but although I've run a few D&D games in those lines, probably most of my games fall into the 2-Uncommon category. Maybe because my players tend to like a bit more magic, or maybe because D&D has a lot of magic-related material in its books and I just feel like using a bit more of it. Nothing against categories 3 and 4, just not my favorite kind of D&D to DM, but I'd gladly play a good type 3 or 4 game too as a player.
So what about you?