I'm a huge fan of Turkish spindles. They are bottom weighted and tend to be very stable. On top of this, when you spin, you create a centre pull ball on the spindle itself, which you can then use to ply with, without worrying about winding the single yarn off for plying.
These 3D printed spindles made by Jen Kemery of Turtlemade have even more advantages than most.
They are extremely well balanced, and have a lovely long spin. They won't break when dropped, which is great even for experienced spinners - we all drop them sometimes! You can also use them as supported spindles as well as drop spindles.