While there are many high-publicized lists of “best” plants for attracting pollinators, those lists are often highly subjective. Even some highly promoted ones unfortunately do undergo a formal scientific vetting process.
Ideally plants recommended for attracting native bees should be developed based upon actual field surveys of bee visitation. Michigan State University provides a nice example here
http://www.nativeplants.msu.edu
In addition to having documented value to bees in field surveys, other factors scientists might consider when recommending plants is their commercial availability and the lack of undesirable cultural characteristics (being weedy, or harboring crop pests and diseases).
Some examples of plant lists developed with these criteria is available here:
http://www.xerces.org/plant-lists/
-Eric Mader, The Xerces Society for Invertebrate Conservation
Bee Informed Partnership