Bob O’Hara has an interesting post on interpreting relationships in ecological data. He notes that the strength of relationships between a response and explanatory variable will be underestimated if error in the explanatory variable is ignored.
This issue is often considered in allometric studies, but rarely anywhere else. We included uncertainty in the explanatory variable in a recent study of avian dispersal distance, but ecologists usually seem to be able to get away with ignoring it. I’ve never known a reviewer or editor to mention the issue.