Seal of Nehahra was an excellent machinima, especially when the entire voice acting was done by one person, iirc. Scourge Done Slick [1,2] is also another well done machinima/film showcasing the speedrunning community.

[1] Part1: https://www.youtube.com/watch?v=SibdQvgsGJo

[2] Part2: https://www.youtube.com/watch?v=XlnDvsa-Ork