PLA & PETG are pretty easy to print and will create practical parts.
For more 'extreme' parts I would check one of Taulman's special filaments at
http://taulman3d.com/how-to-choose.html
And you might find Thomas Sanladerer's new series of videos really informative and helpful:
https://www.youtube.com/watch?v=YcQH...5ZTi2&index=16