http://www.silentpcreview.com/forums/viewtopic.php?t=48290
If you go with a cool/quiet component selection, which you seem to be doing, the Antec 300 would be a fine choice. The stock 120mm and 140mm fans can be set to low speeds and provide sufficient cooling quietly. One of my friends had a 4850 CF setup in one of those. Can't say how quiet the case is, but it shouldn't be particularly loud. Keep in mind that this case has a perforated "mesh" front. This allows for a little better airflow as it provides an ambient cooling effect; I have a case with this feature (Centurion 5), and I can feel my CPU's fan (Freezer 64 Pro) pulling air through the front of the case. However, the mesh front would also make the computer a bit louder, as the solid sheet of metal provides a sound barrier. It's really an unnecessary perk, as the cooling provided by the stock fans would be enough for your build regardless. I believe that the Sonata III with its stock fan(s?) and no mods would also provide you with a sufficient cooling solution. Also, the 300 provides for a bottom-mounted PSU, which is more efficient for airflow.
The Sonata III is, of course, marketed as a quiet case. It has a 120mm tri-cool fan for exhaust, some kind of rubber spacers for mounting the hard drives (reduces HDD vibrations from transmitting throughout the case, making the system quieter), and comes with a quiet, efficient PSU that looks quite in line to power the components you've listed.
http://www.silentpcreview.com/forums/viewtopic.php?t=43151
Apparently the Antec Solo is pretty highly regarded at Silent PC Review. It has sound dampening material as well as a HDD bay that allows you to suspend-mount the hard drives. This is basically a step up from the rubber spacers of the Sonata III.
It really depends on your budget and such. Any of these 3 cases would be superb. The Solo is an excellent choice, probably the best of the 3, if you don't mind dropping $100 on a case without a PSU, since it offers sound deadening as well as suspendable HDD mounts. The 300 is a great all-rounder, offering up the best cooling solution of all 3 cases. The lower price tag doesn't hurt either. This will allow you to run your fans at lower speeds and thus creating less noise than either of the other cases. The Sonata III sports some features that will make it quieter than the 300, but not as quiet as the Solo. The nice thing is that the Sonata III is in the same price range as the 300, when you factor in the cost of a PSU.
Hope this helps!