eye pencil - just a good long-lasting eyeliner
eye kohl - soft pencil specifically for waterline, but can be used elsewhere too!
eye power kohl - stronger colour than above
technakohl - softer texture, easier to smudge, longer lasting, strong colour pay-off - the father of the eye pencils basically!!
powerpoint eye pencil - the mother of eyepencils, its waterproof, smudgeproof, diff. finishes, good colour pay-off.
In terms of which are the best, depend on your requirements. All serve fairly different purposes. I would personally go for the powerpoints and power kohls!
HTH chick!
xxx