I won't wait, really. Considering it's a brand new platform, it will be a while (at least half a year, though most probably more than that?..) till any Linux distro would run reliably enough on this platform and all quirks are worked out. And then you'd have to deal with some platform specific XBMC bugs... After all, it's a brand new motherboard and chipset.
Another drawback I see is lack of _rack space_ inside the case. Eg, in my case my HTPC has three different functions:
- media center (XBMC)
- file server
- torrent client
And while for the first and the last function the 'light weight' setup will work, if you have any significant media library you'll have to setup another file server hardware. Now, it can be a 'function specific' file server (ie, 'off the shelf'), but the price / value is quite poor (normally you'd have to pay over $150 for anything decent, in most cases not extendable, with only two bays for HD). Another drawback is that having torrent client ('writer') and main consumer ('reader'), and NAS on two separate network nodes reduces overall reliability (we are talking soho networks here, not redudant enterprise stuff
).
On the other hand, any mini-ATX case would give you 6 to 9 bays for standard 3.5'' HDs, and standard mini ATX MB will give at least 5-6 SATA connectors (with another 6-8 USB connectors through which you can extend even further via SATA-USB adapters). In other words, in home setup, I found it useful to actually aggregate all functions into one box. All, except for one - custom router, if you need one (for which I'd definitely have a look at the link posted above - THANKS! - or JetWay extendable mini ITX board). But that's purely network gear in any case.
In other words, build your XBMC box today, don't wait another year
.