Most gifs these days is via custom tools that will basically rip the frames and assemble the gif. Just give it a start and stop time, a video file, and grab a latte...
In case I don't have a source video file, one of my personal favourites is peek [1]. A small gtk app that allows you to quickly record a portion of your screen and save as a GIF.
[1]: https://bbs.archlinux.org/viewtopic.php?id=209422