If you have a conclusion, chances are you can find some research to support that conclusion. Or, if not, it should be fairly straightforward to design a research project that will tell you want you to hear. I am being slightly facetious and know that most people do not do this on purpose, however, it is easy to be fooled by unintentional research bias.
Reputable research firms will do everything possible to reduce bias in the sample and questions that are used. However, even the best designed research projects still have some level of bias. Since most organizations have limited research budgets, most research projects end up being imperfect.
To overcome this, I would suggest always seeking out a variety of different research sources before making a decision. If you are making changes to your Web site, look at your metrics and what similar Web sites are doing in addition to analyzing your usability research findings. Also, don't forget to think creatively. Don't be afraid to innovate. Research may be great at suggesting ways to tweak what you are doing, but it is not usually the source of great "Eureka" moments.
Yes, research is important. Just be cautious and don't take it at face value.