Ok, this one has been searched before and I THOUGHT I had it bookmarked, but umm, nope. *smacks self*
The fic I've been trying to find has the car accident in it. The one where Buffy and Xander are riding, Buffy's driving actually, and his dad, who'd been drinking hits them, then flees the scene. Xander's in the hospital when the cops bring in Tony, and Spike nearly goes ballistic and tells the cops that he's definitely the one who hit Xander.