i also considered to crop away more sky, but then i had the dilemma of putting the skater in the crossing point of the rule of thirds or less sky. the rule of thirds had more power in my mind, but i'll try some different crops on my pc.
about the fisheye, i don't really like fisheye lenses. firstly, the effect can
be nice in some pictures, but not often. that's why i think it costs too much to buy such a lens just for those few photo's. i'd rather buy a flash, telezoom or tripod for that money. or when i would buy one i would over-use the lens because i spend that amount of money on it, so i would 'have' to use it.
secondly, as you said, a LOT of skate photographers use fisheyes. i'm kinda tired of the effect now :p... plus, i want to stand out more.
thanks for all the feedback