This is a rather timely thread - I'd been looking stuff like this today.
The motherboard I have supports the RAID options, but I prefer the idea of having a NAS setup running RAID5 instead given the laptops in the house and longer term ideas of an additional HTPC in another room.
There's
this one on EBuyer that does the job, but I'm pretty sure there must be cheaper alternatives given that's an Intel box.