SABnzbd + SickBeard + CouchPotato (couchpotatoapp.com) == what cable should've been years ago.

Sickbeard is indeed fantastic, and it's got quite a bit more polished in recent builds!

Also check out nzbmatrix as a NZB source, it's done me quite well.

Finally, SuperNews is a Giganews reseller that is a bit cheaper if you're looking to save money (though with all that Apple gear it's unlikely).

Also check out the SABconnect++ Chrome Extension.

If you're on a budget, Astraweb are nearly as good as GigaNews, but way cheaper, particularly with this discount: http://www.news.astraweb.com/specials/kleverig-11.multicards...

I tried it a few months back, I didn't end up using it. I felt like it was unnecessary, I rather focus on one app than two. I stuck with sabnzbd+ & nzbs.org, after newzbin was taken over.

Seriously try it out, it might require some time to get it setup in the way that you want, but combined with XBMC it is golden

I actually have SABnzbd running on my low-power NAS, while ~XBMC is running on a dedicated machine with dedicated GPU. I find it advantageous to run the lower power NAS 24/7 and only crank up the graphics-heavy front-end when something needs to be displayed.