My favourite so far has been some gratutious product placement for a bit of mountain-climbing kit in one of the Lost Tomb shows, and then it broke (in-story) and nearly got the main character killed. They wouldn't get away with that in a US drama, I'm fairly sure! I still remember on White Collar when they needed to put Peter in a completely different definitely not Ford Taurus car for a spurious reason one day so they could have a car crash!