In an effort to help you, dear readers, avoid (or at least plummet informed-like into) the pitfalls of moving to Leopard with live projects in the hopper and specific needs like Final Cut Studio, Logic Studio and other pro software, I have decided to take the plunge and just try to make this stuff all work, even before all the lights are green if you know what I mean. As I encounter weirdness, I am attempting to find solutions, and deliver them to you here. My hope is I that I might be able to save you steps and valuable time. Maybe even offer some insight that will fuel the "right" decision for you about upgrading or not, what drivers and apps are working and which ones aren't, and just how to go about making this momentous OS move. I'll be the G-pig.
Ok, this one was harsh. I am running Leopard 10.5 on a new iMac 24" 2.4 GHz, with the 256MB ATI Radeon HD2600 card, 4GB RAM, the 320 stock drive, a slew of FireWire 800 drives chained up, as well as a USB hub with various devices, like an Epson printer, Lexicon Omega I/O, and Samson CU01 USB Mic... I also already have the entirety of Logic Studio installed (49GB), as well as iLife '08, Adobe CS3, and 10 or 15 of my favorite shareware/small developer tools like Interarchy (FTP), BBEdit, SnapzProX, IShowU, Comic Life, Google Earth, MarsEdit, NetNewsWire, and of course World of Warcraft, not that I have any time to play it.
I have also let fly and straight up installed the new QuickTime 7.3 and iTunes 7.5 updates that came around earlier this week. And the iMac Update 1.3 - purported to fix some hardware issues. That I just ran last night. Seems to be working fine (the machine) this morning.
The Problem:
Yesterday was the day to get Final Cut Studio 2 installed on this bad boy, and I immediately ran into a major issue. When I ran the Final Cut Studio Installer DVD, FCP and Soundtrack Pro come up greyed out in the list! Just sitting there dimmed. The installation instruction screen (the one right before "choose which apps to install"), tells me to mouse over the line items in the subsequent screen if anything is greyed out for an explanation. The line item for Final Cut Pro 6, it says TT_NEWERALREADYINSTALLED... see the inset image. If you don't mind my saying so, that "message" seems like it was written in Redmond, rather than Cupertino. But so be it. Well, FCP is not already installed, although Compressor and SoundTrack Pro are, from the Logic install. When I mouse over SoundTrack Pro, the mouse over says something different, like "older version of Sountrack installed, Studio Installs require that it be updated.
The Solution:
As I often do, I decided to search for my issue on the forums, and post the question. I looked on 2-pop and Apple Discussions, and found nothing, so I wrote a post. (Some of the above was taken from the post, so you know what I told them.) That was late last night. This morning, I have a heartily helpful link sitting there on the Apple Discussions post thread, and it connected me to this
article on installing Final Cut Studio after Logic Studio. Wicked! Not sure why my searches did not turn this up, but that's the real trick isn't it?
Final Cut Studio 2: Option to install Final Cut Pro is dimmed
Issue
If you install Final Cut Studio 2 after having installed Logic Studio, the option to install Final Cut Pro may be dimmed so that it is not possible to install Final Cut Pro. Other applications can be installed.
This particular issue specifically occurs on systems on which Logic Studio has already been installed.
Affected Products
Logic Studio
Final Cut Studio 2
Final Cut Pro 6
Solution
Take the following steps to resolve this issue:
1. If it is still running, quit the Final Cut Studio Installer.
2. In Finder, navigate to /Library/Receipts/ .
3. Locate the file named ProMediaIO.pkg and drag it to the Trash.
4. Run the Final Cut Studio Installer again.
Ok, sounds easy enough... let's try it. (Real Time Experimentation here people!)

OK, trashed. I even emptied the trash, even though they didn't say to. Rogue that I am.
Super sweet! It worked, I can now install the Final Cut Studio 2 suite! I hope you have found this post BEFORE dealing with what I did last night. Maybe the secret is always installed Final Cut Studio 2 first and THEN Logic Studio. Has anyone done it already in that order who can confirm that it worked fine? Good luck out there in Leopard Pro Media land folks, seems to be a little bit of a slippery slope so far, but I'm here, your intrepid Mac, Leopard and Pro Media software spelunker. More informed-like plummeting to follow, I'm sure.
Oh, and like a good little Netizen, I posted a follow up on the Apple Discussion board letting them know that the
solution they offered actually worked, and marked the post as both "helpful" and "question answered."
Last night I tried to find a solution for this problem, but I had to give up. Today I found this article, and it saved my day. (Litterally!) So thank you so much for this article! Regards from Norway