What is the best value you have encountered?

Want to gain knowlege from years past. What items can be found used and represent a good value in terms of bang for your buck. For instance I have Polk Ls 50 speakers that I got for $125 dollars and could have had a set of DCM Timewindows for the same money. Everything I read says that the DCM's still hold thier own in terms of performance for the dollar spent. I want to know what items out there perform way above their price point.