I was able to run Windows 7 Ultimate all day. It was convenient, faster than Vista, and has as much eye candy as OS X or KDE. This morning, a few minutes before work started, I installed Windows Live messenger, Office 2007, and Connectwise. All applications worked correctly, except for Connectwise, which was fixed using compatibility mode.
3rd party apps installed and working correctly so far are:

Filezilla
Connectwise
Putty
Sun Virtualbox
Mozilla Firefox
IBM Fingerprint reader software
Western Digital MyBook software
AVG 8.0
T-Mobile Dash Smartphone software