How many DVDs or Blu-Rays do you purchase each year? On average I'd say about 4-5. Definitely prefer physical media since I hate managing memory space.
How many digital downloads do you purchase each year? For video I rarely purchase digital. The digital version of movies I have are usually included with the blu-ray (w/DVD, w/digital download) bundle. I prefer physical media as oppposed to managing available memory space on my devices. However I might choose digital for a portable device like iPad since I load it up with movies for "on-the-go"
How do you purchase digital downloads? (iTunes, Stream, etc) Definitely would go through iTunes. Storing in iCloud is definitely a plus in terms of the managing memory issue. I have also purchased TV episodes through the Playstation Network and downloaded to PS3, very convenient since the download is ready to be watched on the TV as opposed to a computer screen.
Do you download directly from iTunes to your device, or iTunes to your computer, and then transfer to your device? I download directly to my device.
Is a 1.5gb - 2 gb file "too big" for you to download to your device? Downloading a file this big would just take some planning in regards to how long it would take since I don't have the fastest internet connection speed. Memory wise sometimes there is the need to manage space but iTunes definitely has it's advantages with storing purchases in the cloud.