Fairies (or Faieries or Faeries) in the garden?

I looked out of the kitchen window this morning to see a very pretty sight - a group of toadstools pushing up through the damp Autumn earth.  "I think there are fairies in the garden!" I declared. Which led to this train of thought.....

Are they Fairies or Faeries?  Which spelling should I use? And do I believe they are there?

I was brought up reading and writing the word "fairies"  and then when I was in my teens a range of books started to hit the shelves calling them "faeries".  I wondered about this spelling, and even wrote it a few times myself, but just didn't feel right doing so.  Its like the word magic and the alternative spelling magick.  The words all mean the same thing, and are all accepted spelling, but how do you decide which word to use yourself?  Wandering the internet, I find that pagan and magic(k) websites tend to use the spellings that include an 'e'.... does this mean if I declare myself pagan I should use those spellings?  Which spelling do you use?  why?

And then the even deeper question - do I truly believe in fairy folk? 

I believe in nature and the amazingness (OK, now I'm just making up words!) of every living thing.  I'm a trained biologist and teacher, therefore I understand the workings of living things, and still find the life-cycles of plants and animals to be miraculous and awe-inspiring.  I've been pregnant and completely understand the science of reproduction, and yet the idea that a gamete (effectively a half cell) from me and one from my husband came together and from that chance meeting I now have two beautiful and amazing children who grow and think, still blows my mind!

So as I watch my children and my garden grow each day, it isn't so hard to expand my mind and believe that their are creatures that I never see and don't know about, who live around us and enjoy the nature in our garden.  And would it hurt to believe in their magic?  No, I think it makes us better people to believe in some sort of magic - however we spell it.

What do you think?