I checked out the ASROCK board you mentioned. It looks nice, but I prefer a fanless solution. The PCIe slot is an extra, but I have no use for it.
One of my concerns is if I would be getting enough performance to run a torrent client, a webserver, a small database and a mail client while serving files for my home network. Low power consumption is also really important, since it will be running 24/7. That's why I felt like going for an ATOM.
After reading some comments on my posts here and there, I stumbled onto a few interesting things.
Someone suggested to look into Super Micro boards (ex.: X7SPA-H-D525). They seem to have some really nice remote management and they have 6 sata ports onboard. Both very nice features, but they are expensive. In my case it's not the route I feel like taking. I don't need the remote management. The 6 sata ports I could use, but a pci card could help me out to get extra sata ports.
Then I started to look into Zacate. The benchmarks and reviews I found look promising. The mini itx Zacate boards also seem to have 4 or more sata ports onboard...again...I could use them. I'll have to take a closer look, but so far I found this: Asus E35M1-I DELUXE. I must say, It's new, it seems to have nice and usefull features; I like it so far. I hope I can find one in my price range.