For those who want a HTPC, you might want to look at the Zotac ZBox or something similar,
I bought it and at first was disappointing, then I read where I can tell XBMC to use hardware acceleration, as every movie was choppy, even 720P.
All movies play excellent now, but they do not play well outside XBMC using WMC, WMP or VLC.
I think I am probably missing some codec's, I hope

As far as a Server goes, if you plan to stream to more than one room I highly recommend a Windows Home Server or NAS. I have movies streaming to 3 different rooms in my house. I have 5 T of storage and will be adding 2T very soon as I am running out of space. My collection is at 772 movies, and still have 800 DVD's to convert.
If you go this wrought, wire is much better than wireless if you plan on streaming HD. All my 1080P movies were choppy on wireless, but not on wired. I have a Gigabit network infrastructure.
Also think ahead, I started with a 5 port giga N-router, then added a 8 port giga switch, then 2 more 5 port giga switches. But then again why would you think you would need a 24 port switch

Well everything today seems to have a Ethernet connection (TV, XBox, BluRay, Amp...etc)
Someone had mentioned that XBMC does not stream HD audio, please explain? Because all my 1080P movies use HD audio and my amp decodes them. My amp will switch to 2 speakers if it is only stereo, I do not use simulated surround.
Finally can someone tell me how to load up AEON, I downloaded it, but when I try to import it into XBMC, it fails every time.
I am using the latest build of XBMC, and it seems the only way to import Skins is through XBMC Skin menu, and it does not list Aeon.
Thanks