My answer: Unless you know the editor or the publishing house accepts email submissions, give them hard copy.
Here's the reason: Some editors don't want to read new submissions from the screen. They want the hard copy so they can read while eating lunch, riding the subway, or whenever they get free minutes—and there aren't many. If they have to pull your copy down on the screen, it ties them to their desk. If they have to print your manuscript, you've added to their daily load.
Assume that editors are overworked (and I don't know any who would say they're not). Make life easier for them.
Some editors and agents download manuscripts to the Kindle or Sony Reader. But stay with hard copy unless you know differently.
If you're not sure how to send a manuscript,