Two of my most heavily used servers at home can't run 64-bit software. They have dual Xeon 2.8s, 8GB RAM, and run the latest CentOS just fine. They were previously running vmware esx fine. My personal workstation at home is a Dell Precision 650 (and can't run 64-bit software) with dual Xeon 2.8s, 4GB RAM, a nice Quadro FX graphics card, and runs Fedora 14 and Windows XP in vmware quite happily.
These machines work perfectly and perform very well for what I need. What does it matter that they can't run 64-bit software? If I want to run 64-bit software, that's what my SGI Challenge XL running in the garage is for.