Newbie questions

Hello all,

I am a complete newbie to building computers but am excited about the prospect of doing so. I have read quite a bit but am still confused on some things. I'd like to be able to conceptualize what I'd like to build before figuring out the hardware/software. Would appreciate your help.

I want to build an HTPC and a separate NAS.

HTPC: I would look like to build a low-profile (preferably mini-ITX), power efficient, cool-running, and quiet machine. I'm not sure if the mini-ITX case will hold everything.
-Stream Netflix 1080p, Hulu plus 1080p, amazon prime hd, HBOgo, showtime anyime, NHL gamecenter live, NBC sports (for hockey)
-Able to support TWC cable card for live TV. As I understand it, I won't be able to record any non-OTA channels with XMBC right? Is it feasible/difficult to switch WMC for all my recording purposes? Is it difficult to switch between XBMC and WMC? I'd like to not rely on a TWC dvr since they charge $20/month
-Play BluRay and burn to BluRay from PVR
-Able to stream signal to mac, pc, ipad etc
-Can I use only a single SSD in the HTPC if I plan on having a NAS or do I need an additional HD for PVR use? If so, what size SSD and HD combo is recommended?
Is live TV signal in HD and can I record in HD?

NAS: will be wired to gigabit router. Does the HTPC also have to be wired or will wireless support streaming from the NAS?
-Is it possible to rip BluRay to the NAS directly? Do I need added hardware power?
-Is it possible burn from the NAS to BluRay
-BitTorrent capable
-Can be accessible from Mac/PC/iPad
-What speed internet do I need to achieve all of this
-Does the NAS have to powered on all the time? Does the HTPC have to be on all the time?
-is unRAID or FreeNAS best for what I want to accomplish?

Thanks so much for any help in advance!