I replaced the bracket on the GPU with a single-slot bracket from an 8600GT:
I'm hoping that this will allow the card to breathe better and run cooler. It also means that I have probably the only double-slot 8600GT
Here's the finished system:
Ultimately, I decided to go with a 320GB disk instead because it's 7200RPM vs the 5900RPM of the WD 1TB I have. If I run out of storage space, I still have room for two more 3.5" drives. I also went with an Antec 430W PSU, as the 350 is currently in use on the Atom.