WHS is GREAT
Get your facts straight and credit where it's due. WHS is in my eyes the best that's come from MS so far.
The main advantage of WHS is that you can add drives of any size and tech, internal or external and have them increase the storage pool. For Joe home user this is perfect. You place a checkmark on the shares you want to keep duplicated and WHS will make sure there are copies on 2 drives in case one fails. This uses more space than RAID, but the disks are regular volumes that can be mounted elsewhere, unlike RAID.
You can as easily remove a drive from the pool (as long as you have space in the pool to move it's contents).
The backup is also great, it works at the cluster level, this means that if you have 3 pcs on your network running XP, It will only use the space of one copy of it. By default it keeps the last 3 days, weeks and months, meaning you can mount any of those points in time the get a file.
I've built mine with an old athlon 2200 board I had replaced and never managed to get rid of, slapped 3 500GB drives in it and it's been humming quietly in a closet for the last month. I've used 500GB drives as they are at the sweet spot of cost/GB. Once 750 or 1TB drives get cheaper, I can replace them one by one as needed. Let Joe try that with RAID or NAS...
My media collection is at 650GB right now, some of that (100GB of music) is kept synced at my media center, so I don't need that duplicated on the WHS. Half my videos are also burnt on DVDs so those could do without duplication (I keep them duplicated for now to avoid having to reload 80 disks manually in case of failure).
In the states and Canada you can get a 120 day trial for free, give it a try!