what makes a rollercoaster good...fear factor, speed , height or gimmics and do you have any cool pictures or videos

All of the above!

Fear factor and speed!!

You don't need height, the last rollercoaster I went on was Space Mountain 2, and it was in the dark (another awesome factor, by the way!) so obviously we couldn't see how high we were.

And I honestly don't think I would enjoy rollercoasters half as much if I wasn't a little bit scared before I got on them. The fear is almost enjoyable! :)