In Eclipse Helios I have the nice feature of a dependency graph inside the maven pom editor.
This has been removed from m2e 1.0 (previously it was available if you selected 'show advanced editors', but that option is now gone too). The developers behind it have stated that the dependency graph never worked that well with more than a handful of dependencies and the dependency hierarchy view works better anyway.
Here is one of the messages from m2e-users about this:
http://dev.eclipse.org/mhonarc/lists/m2e-users/msg00769.html