I'm not too thrilled with the idea of just adding another external hard drive to the tower.
It's partially because of Windows. Some patch wonked up the file sharing a bit. I add a new folder to one of my shared folders, and even though it's set to allow access and changes, they're "unreachable." I've got disable and reenable sharing for the permissions to stick. Streaming media gets a bit jerky sometimes too, particularly when the tower is busy.
So I'm thinking a stand-alone network-attached storage appliance. Yeah, I could build a linux box and plug in a stack of disks, but that's going to be a bit of a serious electricity drain. There have to be a few appliances in which I could load a few big SATA drives, set them up as a RAID-5 array, and have a bucket of useful storage.
Anybody got suggestions on feature set to look for, or vendors that might be worth looking at?