NBC is the latest huge conglomerate to express distate at Apple over iTunes. Like the Universal Music Group, they’ve decided to not renew their contract with Apple because of disagreements over their policies — i.e., they probably weren’t making enough money off of the deal.

A move by NBC Universal to walk away or withdraw a large amount of content would probably hobble Apple’s efforts to move deeper into the sale of video-focused consumer electronics like the iPhone and a new class of iPods. While Apple’s early efforts in this area depended on music to fuel sales, analysts say video is what will drive much of Apple’s retail business in the future.

The iTunes service wields incredible power in the music business, since it accounts for more than 76 percent of digital music sales. And its influence is on the rise: Apple recently passed Amazon to become the third-biggest seller of music over all, behind Wal-Mart and Best Buy, according to the market research firm NPD.

But the sale of video online is still at a nascent stage. Media giants like NBC Universal are aggressively trying to move into the business — in part to avoid the piracy that has plagued music companies — but the revenue they earn from online video sales does not yet have a material impact on their financial performances.

So some media companies feel they have the upper hand: Apple, for now at least, needs their content more than they need Apple. And there are an array of companies — like Amazon, Wal-Mart, Microsoft and Sony — that would love to have NBC Universal as a partner to muscle in on Apple’s turf.

Then there is NBC Universal’s own Hulu.com, a venture in partnership with the News Corporation to build a video portal to compete with YouTube.

What this seems to mean is more competition for iTunes in the future, which probably isn’t a bad thing at all.

Spread the word!