I guess the worst wipeouts are always the ones that end your season, or shorten it. Luckily for me, haven't had any serious injuries yet...
I was at the top of this super steep run (like a steep black, but fucking steeper) and i slid like a piece of shit on some ice, went down on my ass all the way down, while i couldn't see anything cos of the snow spraying in my face from my skis (was racing at the time, so they didn't pop off). A few seconds later i realised i was going straight to this big lip. Ended up flying over a few people and landing on a hard flat run below, on my ass. Couldn't sit for a few days.