I normally use a wort chiller in my brew pot before transferring to my plastic fermenter based on my *assumption* that hot liquid + plastic bucket = possibly bad combination. To help speed up the cooling process, I also fill a sink with cold water and ice in combination with using the wort chiller. I'm a research scientist for a biofuels firm and my primary duties involve running experiments evaluating yeast metabolism and ethanol production. Its a similar process to brewing (heating material, cooling it, adding yeast, distilling ethanol) and we have some neat toys to help cool down mash, one of which is a large piece of sterilizeable metal that looks like a manhole cover with lots of metal rods sticking out of it. We freeze it and then submerge it, which allows for a huge amount of heat transfer (cooling of the mash) very quickly. I've never tried it at home since my chiller/ice water works fine for me, but you could attempt this if you put a bunch of sanitized metal forks, knives, etc in a grain bag, put it in the freezer, and then dipped it in your hot wort for a few minutes. Your yeast should have instructions on how far to cool it but I typically cool to about 30 Celsius.
