Roku has amazon instant video on it. A big plus for me since I'm a Amazon Prime member and get the service for 'free'.
(Jailbroken ATV has this if you install the Amazon plugin on XBMC.)
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Well, I am familiar with Apple TV (I have 3) and I have 185 movies that are non-DRM that I created. However, with the Roku (I have 1) I have Hulu+ (most important difference), Amazon Prime (I just happen to have it because I do a lot of shipping). However, I much prefer the Apple TV. If they created an App Store where these other applications could be be added I think the other boxes could not compete. Also, not interested in Jail breaking to get the other features.
Got that you are not interested, but perhaps for others:
Amazon Prime and Hulu (both free Hulu AND Hulu +) are available on the ATV. All that is required is you jailbreak, install XBMC, and install the Bluecop repository. Instructions on how to do this are in the
"How to enable Hulu on Apple TV" thread, here. There is very little risk, no monetary cost, and will probably take less than a half hour of your time.
I've seen several people mention that the only reason they have a Roku is for Hulu+ and Amazon Prime. So, if that is a reason that someone is considering buying a Roku in addition to an Apple TV, there is no need. Apple TV has that covered.
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Linked to devices like those from Elgato and you get an fairly easy ability to record high quality video, have the Elgato software save it in an iTunes/

TV file type and even drop it into iTunes for you. See:
http://www.elgato.com/elgato/int/mainmenu/products/software/EyeTV-3/product1.en.html It can be a DVR like experience.
ClearQAM still requires a cable connection and often at least some subscription to cable. Some have found that ClearQAM is available even with no subscription to local cable. And some have found that ClearQAM is available with a broadband-only subscription to cable. You'll have to do a little checking in your local market to see if you can fully jettison cable and still get ClearQAM. If not, you might also look into an OTA antenna if you are mostly interested in free local (network) channel HD.
This is exactly what I do. Broadband through Time Warner Cable (I'm in the Los Angeles area). I don't pay them for cable TV, but I get Clear QAM for free, which gives me all the broadcast networks (ABC, CBS, NBC, FOX, PBS) plus Discovery in HD. I also get some other channels like AMC in SD. I also get good OTA reception, so I could use that as well, but I wouldn't get discovery or AMC over OTA, so I use clear QAM. If I ever want to change ISP's, though, I'd just use OTA.
I use an HD Homerun dual-tuner device to send this signal to my MacBook Pro, which runs EyeTV software. EyeTV software is the "DVR": I use it to schedule the recordings using the same type of TV guide setup you see on a regular DVR, only I can easily type a show name in a search box and click "record all shows". The HD Homerun and EyeTV software are available as a combo package from Elgato for $180. May seem a tad expensive, but weigh that against the monthly cost you are paying for cable/dvr rental and you'll see that it won't be long before the devices have paid for themselves.
After recording, EyeTV exports the show to iTunes so that my Apple TV can see it. Now that recording, sitting on my mac, is available to both the Apple TVs I have in my house (one in living room, one in bedroom). So Apple TV is our new DVR.