The Eclipse plug-in also features a DFS browser.
Yep. That's all true, I don't mean to self-promote, because there really isn't that much to advertise ;) I was just quite attached to file manager-like user interface; the mucommander clone I posted served me as a browser, but also for rudimentary file operations (copying to/from, deleting folders etc.). In my experience it's been quite handy.
It would be probably a good idea to implement a commons-vfs plugin for Hadoop so that HDFS filesystem is transparent to use for other apps.
Dawid