Have Tiger, but lots of old apps... should I pull the trigger?

Question

Yes, I know this is a popular question, but every situation is different and I haven't seen a definitive answer after browsing the forums for a while.
I have the following hardware:
800MHz 17" flat-panel iMac
800MHz iBook
...and the following apps, none of which I can afford to upgrade:
Final Cut Pro 4
Premiere 6.5
Illustrator 10
Photoshop 7
DVD Studio Pro 1.5
Lightwave 7
Cubase SX
Logic Express 7
Flash MX
Office X
ProTools FREE (v5 - OS9 only)
...and probably a couple others I've forgotten.
I was given the retail box of 10.4, and the temptation is SO strong to install it. My two Macs were bought at times when I had an unusual amount of cash, so in the future, I think my limited budget means that the only new Macs I'll have will be Intel machines of er, let's just say an un-conventional nature. I also can't afford to upgrade the apps, although I do have Soundtrack Pro and DVD Studio Pro 3, although I still plan to use 1.5 most of the time. I may also be able to use Photoshop CS2, but sticking with 7 would be fine.
My biggest problem is with FCP4. I've heard that QT 7 really causes problems, not the least of which is no QT Export to MPEG-2. I of course have Compressor, but get the constant "unable to connect to background process" error, so I rely on QT Export to create .m2v files for DVDs. I guess it's possible that Compressor will magically work in Tiger, but I fear letting go of QT Export. I also dread paying for a new MPEG-2 Playback Component and/or QT Pro license.
I wish I could cross-post this into the FCP and DVDSPro forums, but hopefully enough people here will be able to tell me whether I'm better off not upgrading unless I can get new versions of the apps.
My application for the iMac is audio/video production, and even though it's done well up to now on the stock 256MB, I'll be upgrading the ram soon to the max of 768MB (that's the max without opening up the case, which I'm hesitant to do). I also would like to use the iBook for some field work, and given its 30GB hard drive, I don't see partitioning as an option. On the up side, the iBook does have the absolute maximum of 1.125GB of RAM.
I would of course use an external drive for content on both machines, but at least with the iMac there's an 80GB hard drive that can be partitioned and still have ample room. I currently have most of it assigned to Jaguar, and a 10GB partition for Panther. If I went that route again, the Panther partition would have to be larger than 10GB because most of the apps would be installed under Panther. I guess another issue is whether Tiger and Panther partitions would play nice. Right now I can launch applications that reside in the Panther partition even if I booted into Jaguar and vice-versa, but I wonder if that would confuse Tiger.
Anyway, thanks in advance for any advice.

Answer 1

I apologize for the tone of my previous post, but it's so frustrating to post a question and have so many people "miss the barn" in their answers. Funnily enough, you actually have a very similar collection of machines to me... I have the 17" FP iMac, the iBook G4, and also a B&W G3 in the bedroom that my fiancee and I use for web surfing. I tried posting in the FCP and DVDSPro forums since those are the most important apps to run, but not much response.
What I ended up doing was creating two equal partitions on the iMac (~37GB each), one for Jaguar and one for Tiger. I actually like working in Jaguar for daily computing tasks, so I'll be installing my older apps there. My recording interface won't work under Jaguar, so my audio apps and all newer software (Soundtrack Pro, Adobe CS2, etc.) will be installed on the Tiger partition. I have no love for Panther, so I've stopped using it completely.
I'm sure switching between the partitions will be somewhat of a pain, but the option-key startup menu should make it easier. As I mentioned earlier, when I got Panther I only made a partition for it rather than upgrading, even though my apps would still run. I just didn't like the metallic look. Apple had started adding brushed aluminum in their hardware, but the Aqua interface seemed to go better with the older "iLamp". It's funny though, I really like the look of Tiger on it, maybe in part because they went back to a blue Apple Menu logo. It also seems quite snappy, although the first few boots on my iBook were painfully slow.
I haven't bothered to upgrade the OS on the B&W... can you really get it up to Tiger? It does have built-in Firewire, but I thought the minimum clock speed was something like 700MHz. It doesn't have tons of RAM either, so I'm probably better off not trying to upgrade. It seems to have a Rev. A motherboard, so it crashes once in a while, not very often though. Also, the Firewire is either disabled or fried, because I've tried an iBot webcam and it couldn't even see it. I'd hazard a guess that the reason the B&W might seem snappier is because the OS knows it's on an older machine and turns off a lot of CPU-draining eye candy that you may not notice (font smoothing, shadow effects, etc.) so it looks about the same but runs faster. Whenever I'd run OS 9 on my iMac it seemed like a screaming little machine compared to the previous Macs I had, but not so much with OS X.
Well, thanks for trying. I kind of figured this out myself, but I would have thought that someone here would have had the same experience as myself and could offer some advice. Seems most of the posts here are about upgrading to Leopard, so I guess I'm a bit behind the curve. For now, it's kind of comforting that I can't (officially) go beyond 10.4.11, since it makes the decision for me. Of course once an app comes along that only runs under Leopard, that sick feeling of being obsolete will probably come back.