Some excellent news: Qt is soon to be released under the LGPL. Long story short, this means you can now use Qt for commercial projects (provided you’re careful and understand how the LGPL 2.1 and provided you don’t modify the Qt libraries) without paying the old $4995US fee.
They’re still providing the “commercial” release for people who want to pay for it. I suppose in some circumstances companies might need it, depending on what other code they need to interface with, but for the majority of new projects the LGPL license is perfect.
I’d always shied away from Qt in the past because as good as it is, the licensing was too restrictive for some of the things I wanted to do. But combine this news with the fact that Qt 4.5 will support 64-bit Cocoa for app creation and I’m already planning on using it for my next personal project.