I created a web project with maven like this:
mvn archetype:create -DgroupId=com.mycompany.app -DartifactId=my-webapp -DarchetypeArtifactId=maven-archetype-web
You can also use mvn eclipse:eclipse -Dwtpversion=2.0 to generate all WTP meta-data for the project without changing the POM.
mvn eclipse:eclipse -Dwtpversion=2.0
Of course, you'd have to change the WTP version if you are using an older version of Eclipse.