Help! I know nothing about beading threads and needles - and I'm getting really confused.
There's lots of different threads out there. My favorite online bead store - Fire Mountain Gems has this to say about beading threads and needles:
Nymo nylon beading thread has become the most popular choice for working with seed beads. It's lightweight and comes in a variety of thicknesses and colors. Be sure to use beeswax or Thread Heaven to coat and prevent it from fraying.
Tips: Use only size "D" and lightweight beads with smooth holes for stringing. For loomwork, use size "D" for the warp and size "B" or "D" for the weft. For off-loom beadwork, use the heaviest size possible for the type of work you're doing: If you are passing through seed beads more than three times or are using size 15-2 seed beads, use size "O" or "OO"; for other off-loom projects use size "B" or "D". Any needle listed below works with this thread, but if you choose a beading needle, be sure the eye isn't too small for the thread weight you've chosen. You don't want the needle to be the culprit in wearing out your thread.
Kevlar is a very strong synthetic material. So strong, in fact, it's used to make bulletproof vests!
Tips: This thread works best for stringing and you can use any type of needle listed below to work with it. When securing Kevlar, use a fisherman's knot to ensure its continued strength. Kevlar is naturally yellow, but can be dyed any color using fabric dyes.
Silk is the most traditional thread for stringing pearls, but the thinner sizes are also useful in making other beaded pieces. This natural material has the widest range of sizes, as well as the largest variety of colors of any of the materials listed here.
Tips: Silk often comes on cards that include a needle already attached to the thread. You can use any of the other needles listed as well, but, as with Nymo, be sure your needle isn't wearing out the thread. Because the ends fray so easily, silk is sometimes difficult to thread onto a beading needle, so a Big Eye needle might be easiest. If stringing, only use with smooth-holed beads so the thread doesn't become weak from abrasion. Size "D" works well for light weight beads, size "E-F" for medium weight, and size "F-FFF" for heavy weight. For off-loom or bead embroidery, use size "OO-D", and be sure to thoroughly prepare the thread with beeswax or Thread Heaven.
Silkon Bonded Nylon Thread is a synthetic material that looks and drapes like silk, but resists fraying and has incredible strength. It comes in light, medium, and heavy weights, and in a wide array of colors.
Tips: Silkon is primarily used for stringing beads because it is so strong and durable. You can use any type of needle listed with this type of thread, but, depending on the weight you use, it may be easiest to use a Big Eye needle.
Beading needles are very thin, flexible needles most often used for seed bead work. The advantage to using this type (rather than regular sewing needles) is that their eyes are the same width as the rest of the needle, so there's no added metal width to get in the way as you pass through seed and other small-holed beads. These needles also come in a twin-pointed version (used for bead embroidery) and a glover's version (these have a triangle tip used for leather bead embroidery). Use for bead embroidery, loomwork, off-loom beadwork and stringing.
Big Eye needles are extremely easy to thread. They feature two sharp ends with tension wires down the middle that can be split; simply open the wires and pass the thread through. Use for bead embroidery, loomwork and stringing.
Twisted beading needles are primarily used for stringing beads because they don't have a sharp point. Their wide eyes are easy to thread, and collapse once you pass through the beads. Use for stringing.
There is also Silamide thread, which is a pre-waxed twisted filament nylon thread. It's pretty popular also. But it's thick so you wouldn't want to use it if you're going through beads more than once. This is one of those things where you have to try the different threads and find what you like to work with.
Hope this helps!