Using Apple TV: Need to have iTunes running at all times?

Hi all-

I'm considering getting an Apple TV to use as my home entertainment center, but first I'm trying to get a bit of a sense of how it works, and it's hard to get a sense of some of the details. I know that if I want to watch movies I've downloaded from non-iTunes sources, I'll have to import them into iTunes on my Mac and then leave iTunes running so that the Apple TV can stream them. But I anticipate that a lot of what I'd be doing with it is renting movies or buying TV shows from the iTunes Store, which it looks like you can do directly from the Apple TV interface. Would I need to have iTunes running on my laptop to watch videos I buy/rent in this way? Would I need to have iTunes running to watch Netflix or YouTube videos on the Apple TV? Just trying to get a sense of how dependent the thing is on a computer running iTunes; my computer is at the complete opposite end of the house from the TV, so it'd be a pain to have to run back and forth.

Thanks in advance for any info you can offer!