Software RAID and hardware RAID are essentially the same thing, RAID 0 which merges the drive space into one big lump (and would give you your 4TB) increases the chance of any one drive's failure destroying all your data. RAID 1 is mirroring one drive's data onto the other - effectively giving you a live backup of your data - but as you say could be considered 'wasting' the extra 2TB. It all depends how much you value your data as to whether you want to choose either, really.

Let me start by saying THANK YOU for this guide!  I've been reading it over and over for a month and drooling.  I started my project with a WD Live Streaming Media Player and that sucked.  Today I got a Boxee Box.  It isn't exactly an HTPC or XBMC, but so far I'm loving it.  I did go with Astraweb/Sabnzbd/SickBeard/CouchPotato, though.  I'm just using my main PC's slave drive (2 TB) to store media and NFO.  Boxee can do it's own metadata but I'm using SickBeard's XBMC database.

So on to my question... it's about storage size.  Currently I'm just using a 2 TB drive as I said.  In your guide, you said you always prefer 720/1080p... and I do as well.  However, up until now I've just been downloading DVD Rips and normal "HD" televised versions which run anywhere from 350mb to 750mb for a 1 hour television show.  After downloading my first 720p BluRay episode of The Walking Dead with this new setup, I noticed it's about 2.3 GIG!  Just one episode!  Obviously, the quality is much better, but now I'm concerned about how much I'm going to be able to store if I keep with this quality preference...

How much storage space are you 720/1080p guys typically using for this purpose?  How much storage space does Windows 7 support?  I can add another 2 TB drive I suppose...

This setup is so slick.. I know I don't have an HTPC but even using SickBeard/CP/Sab etc. on my own Windows 7 Box and using Boxee as the streaming device.. it's freakin awesome.  Now I'm half tempted to rip all of my BluRays and sell the discs!  Yeah right... like I can afford to lose that HD space

Well I'm back in the UK now, once I get a bit of spare time I'll update everything and redo the guide

Nice Guide

Can't wait until you get time to update it

Been going through what I need to update and there isn't too much that is actually 'out of date'

Couch Potato is running a beta of V2 which I'm going to try out and if stable (which it looks to be going by comments on xbmc forums) I'll update guide with that. I also want to add Headphones (Music downloader) to the guide however its having major issues with pulling Album information at the moment so I'm going to hold off until that is sorted.

The new version of XBMC has some small changes and there are some skin changes as well which I need to play around with but haven't upgrade myself since coming back into the country 

I'm running Eden and its nice, like you say, minor changes really. I think its slightly less stable than the previous version, running it 24/7 it occasionally locks up which I never had before.

I'm running a shared XBMC database now so all my machines can access the same library, I've found the performance worse and you still need a version of XBMC running constantly to handle real time library updates as there isnt a headless version. The full backup and restore of the library didnt work fully so it was a huge task to update all the films again. So in summary, not worth the effort.

My XBMCbuntu Eden machine is very slow to boot (using an old mechanical drive) which has meant its hardly ever used. I had to replace the Nvidia card with an ATI one to get it running as well. Need to put a small SSD in there to finish it off.

Still working on my paper notes / draft versions of updates but wanted to highlight a current problem with NZBMatrix and Sickbeard.

NZBMatrix has complained that SB is hammering their servers so they have 'blocked' lookups from SB. As SB uses the RSS feed and not the API to grab info from NZBMatrix its not a 100% fail but you will probably be seeing lots of errors in either sickbeard or shows just not correctly adding to your SAB queue.

There is some complex way around this (which I haven't looked at myself yet) if you do some googling but for the moment I've just disabled usign NZBmatrix and enabled SickBeard Index and added NZB.su as a new provider.

Best thing to do is setup notifiys as I explained in the guide. So when SB or CP finish downloading the show they tell XBMC to update. The main difference is that you will need to put in the IP address of XMBC on the raspberry pi instead of the local IP of the server.

In Sick Beard you can have multiple IP's (seperated by commas) as long as all XMBC installs are using the same username/password.

Couch Potato doesn't say anything about multiple hosts, I can't find anything with a quick google and I don't have 2 XBMC's setup to try for you but would be interested to know if it does work if anyone has tried?

You can also set XMBC to rescan for media on each startup but this will only be useful if the machines aren't on 24/7.