Bear in mind I'm just recently turned 15, so anything 75 mph+ is serious wheels for me.
I've faced a friend of mine (not that day) Steven Singh, who's the opening quick for Prahran's 1st XI. Regularly 130kph+, with copious accuracy.
One of Dandenong's 4th XI opening speedsters, known to me only as Jordy, came off about 6 steps, and sent down a "loosener" which crashed into the back of the net without a bounce at easily 120kph. Then I hear our 1sts coach yell out "So you ARE just as quick off 6 steps!". Then he yells "DaanalSeed, hop into this net here, mate".
Those are the quickest I've faced, although I've seen Brett Lee and Mitchell Johnson bowling in nets next to me. You really can't see the ball!