Your question is both simple and complex at the same time - depending on who you ask. Large, commercial honey packers strive for mainly two things: uniformity and long shelf life. They blend honey to achieve uniformity of taste so that the honey you buy today, tastes like the honey you bought six months ago and will taste like the honey you buy a year from now. Most American consumers want (even expect) this. And since granulated (crystallized) honey is not visually appealing to most American consumers, they also finely filter and heat the honey to substantially increase it's grocery store shelf life. I keep mentioning 'American' consumers because in other parts of the world, creamed (crystallized) honey spread is more the norm - not liquid honey.

If you ask these questions of beekeepers, you're likely to get different answers and perhaps, in far greater detail than what you'd get from commercial honey packers. It's true that occasionally even on the grocery store shelf, you might see varietal honey for sell like clover, alfalfa, or tupelo mentioned on the label. But since most large packers blend their honey, a specific floral source isn't mentioned.

For a description of some different honey flavors, you might check the beekeeper's bible, "The Hive and the Honey Bee" or simply do an internet search on this topic. I think you'll find that most attempts at trying to describe flavors with words, ends up reading like something written by a wine tasting judge (...a light, fruity flavor with a hint of nutty overtones). Good luck!

Honey flavors (and colour and even smell) vary widely depending on the available nectar sources the bees have to work. Even in my own beeyard, it's always like opening a Christmas present every year to see what kind of honey I get from my bees. No two years have ever been the same. Since the bees get their nectar from blooms in the local area and what blooms (and for how long) depends on temperatures and rainfall, there is almost always a slightly different mix making up the honey I get. Of course, there are some general rules, honey take from the hive in the Spring is usually light and very sweet; while honey taken in the Fall is usually darker and stronger flavor. And of course, if beekeepers are careful and plan accordingly, you can get the varietal honeys by having your beehives in the right location at the right time and a large population of nectar foraging field bees. This is how specific varietal honey is captured (Tupelo, Basswood, Sourwood, Fireweed, Orange Blossom, Mesquite, and on and on and on....) - I wouldn't attempt to name them all; many are local to only one region of the country where that particular plant grows. Most small scale (i.e., hobbyist) beekeepers don't move their hives around the country so they tend to collect the 'honey flow' (nectar flow) only in their local area and since they can't control their bees' nectar sources, they simply refer to their honey as "wildflower" honey (kind of a catchall phrase).

Health benefits? humm... that's a whole topic unto itself. I suppose you're referring to the trace amounts of pollen in raw (unprocessed) honey? There's lots of information on the internet about this topic. I tend to come down on the side that believes there is something beneficial to the pollen/allergy thing that local honey supplies. You can even search this forum - we had a discussion about pollen not too long ago (perhaps a month or two back).

txbeebuy did a pretty good job answering the question.
As far as health claims there are hundreds of websites out there with thousands of claims. Some with a good basis in fact, others are questionable. I found one the other day selling honey and actually claimed that you can't get fat on honey (I guess because the calories from honey are somehow special and don't count like calories from any other food. If you believe that I've got a magic cure for Varroa to sell you too :) So do be aware of the source of the info.

That said, the following link answers many of your questions: http://www.wholehealthmd.com/refshelf/foods_view/1,1523,283,00.html

I've seen a few descriptions of the varieties of honey, but know of no resource that describes even a good fraction of the 300+ there are.

Here is a link that might be useful: Honey Info