This is a common question I get from sellers on a daily basis. The quick answer is to disclose anything and everything that you would want to know if you were the buyer. If this does not resonate with you, then how about disclosing all current issues, and all past issues that have been repaired. When you disclose everything you have no disclosure liability after you sell your home.
The big ticket items that often end up causing law suits are moisture intrusion issues such as past leaks, floods, other water related issues and mold remediations. Many seller are misinformed and think that if they have repaired a roof leak or remediated mold in the past they do not need to disclose it. They are dead wrong! Of course, there are many other issues that need to be disclosed like robberies, non permitted remodels, noise nuisances like a dog that barks for hours at time to name a few. In this litigious world we live in, I always advise my sellers to over disclose so that they do not get caught in a law suit down the road.