For me personally, it is perfectly working junked electronics - flat screen TVs, amplifiers, speakers. It's amazing people throw away this stuff. It's almost like they decide to upgrade to a newer model and couldn't be bothered selling off their old (but not necessarily obsolete gear). I have been lucky to salvage electronic gear still working after light rain, as the moisture did not get into the components. It might be asking for too much but I wish they left the remote controls with the equipment they are throwing out. Some fresh batteries would be nice too :)
"Waste not, want not"
"One man's trash, is another's treasure"
What is the best free stuff you have found from kerbside collections?