Oops, sorry, I meant Final Cut Pro 4.5.x , not Final Cut Express (which is only at 4.0 right now).
The basic rule to go by is using the software version that was up-to-date when the hardware was current. With FCP 4.5 (alias FCP-HD) you could even handle DVCProHD quite OK (but not HDV). While FCE is offering most of the features that FCP has, I think that one thing for any serious pro is missing: logging plus batch capture.
So, better get yourself a license of FCP 4.5.
Regards,
Uli