district 9 easily jumps to the top of my list. (57 seconds in)
[youtube]pHihFA8q8xI#t=57s[/youtube]
how to train your dragon was loaded up with tons of cool sounds
[youtube]88x08ePynt0[/youtube]
Lord of the rings Balrog (made with concrete and wood!)
[youtube]JLclk16PtE4[/youtube]
also the mouth of sauron was fun.
[youtube]8FfRRpRAHI0&feature=related[/youtube]