Advice needed

All of the available home server nas info is overwhelming.
I have been researching nas devices for more than 6 months and am in decision paralysis mode.
Here's what I need:
1. Media Storage. Have iMac with attached (via FireWire) 2tb ext drive for video. Have 3 young kids and want the nas to be future proof. I know that using our hd video recorder will necessitate plenty of storage for pics and home video.
2. Media storage for video. We own every pixar movie, kids movie, etc. I've hesitated putting them all on the iMac (will run out of room). The ones I have were ripped in an iPad compatible format ( great for airplane flights). Clearly this format is not optimal for our hd tv sets.
3. Streaming. Once I purchase the nas, will purchase units of some type to reside next to our 3 hd tvs play the ripped video. Currently have a Sony blu ray player which can only play a limited number of file formats stored (currently not verions i have on iMac). I am getting frustrated running around the house trying to find the one dvd they want to watch. As a techie, I want it available much more easily.
4. I travel a fair amount and want the ability to access the media data on my idevice or android from a network connection.
5. Want the grandparents to have the ability to access the media data.
6. Want to be able to store some of my work data (projects, limited pictures, videos, etc) from a desktop pc and laptop pc to the device.
7. Data needs to be accessible via pc and Mac os.
8. TV shows. We have comcast, and no TiVo devices. My wife is a Greys Anatomy junkie and would like o have access to the recorded video from any tv(living room and bedroom at a min).

I have a computer background, am a diy-er but am 20 yrs removed from programming. I enjoy debugging problems, but job and3 young kids prevent me from having much time to attack complicated problems or set up issues.

My questions are:
1. Which device? I've already decided on a readynas - too many things seem to be missing from the competitors, too many negative posts and the forum and support here is awesome. I'm leaning toward the ultra 4+ vs ultra 6+ vs pro 6, but don't think I need the business features of the pro model but may need the faster chip speed. Thoughts?
2. Do I need to be able to transcode? It is difficult to find an answer. Given that I have hd sets, I'd like to rip the DVD or blurray at highest resolution, but will need to play back on iPad, iPhone and droid devices. Some recommendations have been to rip 2 copies (at 2 resolutions). This seems overkill. Will orb handle this? If so, how hard is it to get orb up and running on the pro6?
3 I experimented with xbmc on my iMac and liked the UI. The interface is the characteristic of the media extender (popcorn hour, xbox ps3, wdtv, etc), but xbmc does a nice job accessing movie metadata. How does one copy the video, create metadata, (from the disc or download from the web)? Is there a way to access the data and store it on the nas such that it is accessible by different extenders?
4. Is it simple to set up the file system to store the videos?
5. How does readynas photos compare to iPhoto?
6. How does one capture cable tv to the readynas? Do I need a Happaugue device?

I am sure I forgot a few quetions I know these are redundant and that each answer is likely to be found elsewhere on the forum. However, I think the answers will be helpful to many of us who can't decide which nas to buy.

Thanks!