Toye's 1:14 with the chicane is so impressive and just flying around that little track. That sets the actual bar for a pro racer.
For the rest of us, anything under 1:20 CW is what I would consider "fast". Like Stu said earlier, 24's are a fun quick pace but I have yet to break into the teens or even a 20 in the few times I've ridden there. It's all subjective really, if you run 30's a 25 is fast…if you run 20's, a 18 is fast and so on.