BTW, I've never played a tabletop game of 40K either (though I intend to, once I've got a playable
army completed).
Up until the release of the PC game "Dawn of War", my impression of Warhammer 40K was based on vague memories
of reading some second-hand copies of White Dwarf 10 years ago (yes, seriously!) and I didn't really appreciate the difference between the Epic and 28mm games, or even between 40K and Warhammer Fantasy. I had a vague mental impression of small, rather crude and undetailed, cartoony pseudo-fantasy tanks and vehicles.
However, DoW showed me just how impressive and atmospheric the 40K world really was, and how cool some of the vehicle and troop designs were - it made me a near-instant convert!