There are literally thousands of different dart sets on the market today. Trying to work out which type or weight of dart to buy can seem very confusing. Its very much a matter of personal choice, but there are a few basis things to remember when buying.
Tungsten is used in darts primarily because its a very heavy type of metal. This means that less metal can be used to create the desired weight. If, for example, brass was used, the barrel would be a lot bigger than a tungsten dart of the same weight. A smaller barrel is of course desirable, as the darts will all fit more readily into the treble bed (hopefully!). There will also be less chance of deflections.
So generally, the more tungsten content in a dart, the better quality. Aim to purchase a set of at least 80% Tungsten. Professional dart players will use darts of usually 90/95 per cent tungsten, sometimes as much as 97%. The golden darts that you sometimes see being used by professionals for example - these are still Tungsten, but they have a golden coating - slightly different grip feel, but lets not get too technical about that right now. Again, its personal preference.
The average weight of a dart that you should consider would be in the range of 20 grams to 26 grams. Anything lower or higher than this range would be considered a very light dart, or a very heavy dart.
Taylor generally uses fairly heavy 26g darts. The most popular weight for most pro's is around the 22/23 gram mark.
There are many different dart set-ups to choose from. Flights come in a variety of colours, shapes, and sizes. Stems also come in a variety of materials and lengths.
You will only know what suits you by trying various set ups. Buy a set of short stems, and long ones too, and some various shaped flights. Try different setups, but dont just try for a few throws. Try accustomising yourself to a particular setup for say a week or so, and then perhaps try something else for another week. After a few weeks, you will see that one particular setup works for you better than others. We are all different. I use the exact same barrels that Taylor uses, but with short stems, and I like the RIBTEX flights. Target Vision flights are superb. I've tried many different setups and barrel shapes and weights, but nothing works for me better than the Phase 5 Unicorn barrels. You will find that just by changing a stem length, this will give the dart a sometimes completely different "angle of attack" when thrown.
Choose your darts, play with the setups, and you will eventually settle down with a set that works well, and you feel comfortable with. Like a golfer with a putter, you may stick with that set for years, or change your setup every time you feel the need to freshen up your game.
I sell a huge range of darts with various setups, and many different accessories. Try a few out!
Hope that helps a little in helping you to decide. Enjoy your game.