For example, Google Scholar does a pretty good job at locating cases, but it's not the best place to start looking for state statutory research.
So, is there one resource that serves as a one stop shop for all legal issues? Not really, but there are a lot of aggregate sites out there that can serve as a launching pad because they have done all the leg work and collected relevant links to authoritative resources.
Perhaps I'm biased, but I think Law Library Research Guides are a great place to start your research.
As Renee points out in her post about the Massachusetts Trial Court Law Libraries, trial court library websites are somewhat of a "professional secret" among law librarians. There are a variety of ways to locate state specific laws, regulations, and court rules on these sites.What's great about these sites is that they are created with the general public in mind, so you don't have to be a legal scholar to navigate through all the material.
Some of my other go-to sites include Findlaw, Findlaw for Legal Professionals, Cornell's Legal Information Institute, and Alllaw.com. Got a favorite site? I'm curious to see what other free sites people prefer and why.