Check into audio carefully first, if you want to use OpenSolaris as your HTPC. I've been having trouble getting SPDIF out to work on an Intel DG45ID, even with build 117. Haven't tried 118 yet, nor Storm's particular distro.
OpenSolaris is in the process of integrating a version of OSS called Boomer. This will be fantastic once finished, in my experience - I've always have more success getting OSS to "just work" than ALSA.
I do have an OpenSolaris file server in the home to store all my digital stuff. ZFS will blow your socks off with its features and ease of configuration. From there you just share what you want via NFS to your other systems. Don't even need much of a hard drive in your end systems, you could use a small SSD.
Just research your components carefully.