Added the wikitable styles to en.wp's MediaWiki:Print.css for now.

I see you removed the blue background from it http://en.wikipedia.org/w/index.php?title=MediaWiki%3APrint.css&action=historysubmit&diff=361932415&oldid=361917399
Is it being used anywhere?

I agree on removing #f9f9f9 / making it white since it's not distinguible.

For the record: wikitable was added to shared.css on r48842

the blue background

Nevermind. I blame Titoxd for changing the colors on mw.org http://www.mediawiki.org/w/index.php?title=MediaWiki:Common.css&diff=86510&oldid=79323

Yes, someone suggested leaving out the backgrounds when printing, and I kinda
agree on that.

I'm somewhat in doubt over the header background though. On the one side, no
background is probably better readable when printing in b/w or grayscales, but
without a background, it's more difficult to distinguish the headers from the
rest of the tablecells. Only bold is then left as an indicators...

Fixed in r66535