I do love my WHS box. Mine is currently a Pentium E2180 w/4gigs of DDR2 on a Foxconn G33 mATX motherboard. It's in an old Antec Sonata I think it was...whatever their old huge HTPC case was, it kind of sucks but it works. I use a cheap SIL based 2port RAID card just for the extra sata ports.
As far as the Atom goes, I think it depends what you plan to do with your WHS. If you're just going to run the standard WHS setup, where you use it as file storage and for PC backups, I'm sure it is fine. Personally I run quite a few extra things from my WHS that I wouldn't be able to use an Atom for. (I also have 5 other Atom based machines around the house for various uses). Also, I'm not sure if Atom will work with Vail or not. Peruse the
www.wegotserved.com forums, I'm sure they've tried it already. I do know Vail is supposed to be 64bit only. Also if you do go the miniITX route, make sure the MB you pick has enough SATA ports...some only have 2.
I do like that Lian Li ITX case though.
As far as hard drive failures...I just got hit by a couple of WD Green drive failures (one 1.5tb and a slightly older 640gig). Thankfully WD RMA service is great and I got replacements quickly. WD sent me a different model # of the 1.5tb and the PCB is markedly different than the one that failed. I have a feeling they had a problem with the early green drives. So far both replacements are fine. (they sent me a Black drive to replace the 640gig Green...that got put into the wife's PC). Unfortunately one of the drives that failed was my system drive, so I had to rebuild. WHS' rebuild procedure basically builds your storage pool based on files it leaves on each of your data drives, so you don't lose any data. You end up having to re-install your Add-ins, setup your users again, install any seperate software you installed. It wasn't too bad really.
The other failed drive was a data drive. I enable folder duplication so replacing that amounted to telling WHS to "remove" the drive from the pool, and then take it out and RMA it. WHS then duplicates the data again to another drive if available.
After getting my drives back and purchasing another, this is my current HD setup:
2tb Samsung F3
1.5tb Seagate
1.5tb Seagate
1.5tb WD Green
250gb Seagate System drive.
Though I do prefer Samsung drives in most cases, I do like having different makes of drives, I'd hate to buy like 8 of the exact same drives and get a bad batch and have them all possibly die around the same time, that's when you can be hosed. The Samsung's perform well, are completely silent, and I've yet to have a failure of one (knock on wood). They also seem to operate cooler than my Seagates or WD's. Granted my Seagates are 7200rpm drives. If I were to do it from scratch today I'd probably go with a combination of WD Green drives and Samsung's 5400rpm drives. (yeah, I had some WD's fail, but their RMA support is so good and fast that it's hard for me knock them too much...these are the first WD failures I've had in years anyway).
This was probably a lot of rambling but maybe it helps some.
Again, the
www.wegotserved.com forums are a great resource.