I manage Digitization and Digital Curation Services at Emory University Libraries. A huge fan of the ultimate crowdsourced encyclopedia, I no longer look back with nostalgia to the World Book Encyclopedias my parents bought me as a youngster! My participation in Wikipedia is somewhat skewed towards giving better exposure to Emory's digitized resources, but I have a view to a win-win strategy for the community at large as well as for Emory's reputation. While I link to online Emory resources, my philosophy is to never overwrite a link to the same resource digitized by another institution and cited in a Wikipedia article -- unless, importantly, I can establish that our digitization efforts are clearly superior. It's all about you, the "end user" and what best serves your needs.
I try to write new articles when I can (whew, time consuming to do it half decently!), to enhance other's contributions, and to add citations to online resources regardless of the source, as long as it is reputable!
I love that Wikipedia has reached out to libraries and archives to help improve it for the benefit of all, and I strive to be a good citizen in this movement. Libraries must understand that they will never attain Wikipedia's standing on the internet, learn to meet learners and scholars where they find information (i.e. here), and to do our best improve communal information and knowledge.