It is easy to lose track as to which version of Final Cut should go with the plethora of Quicktime and Mac OS versions. But help is at hand.

Jon Chapell at the Digital Rebellion has put together a nice recommendation of which Final Cut Studio/Final Cut Pro versions go best with which QT and Mac OS versions:

Final Cut Pro Version	Mac OS Version	QuickTime Version
6.0.3	10.4.11 / 10.5.2	7.4.5
6.0.2	10.4.11 / 10.5.1	7.3.1
5.1.4	10.4.9	7.1.6
5.0.4	10.4.9	7.1.6
4.5	10.3.9	6.5
3.0.4	10.2.8 Update 2	6.2
3.0	10.2.8 Update 2	5.0.6
2.0.2	9.2.2	5.0.1
1.2.5	9.2.2	4.1.3
1.2.1	8.6	4.1.1
1.0.1	8.6	4.0.3
1.0	8.6	4b16