Mac OS Tiger ...

Will it be compatible? Should I even try it? Does anyone have a clue here about this? I want my 64 bit OS and I want it bad, but not at the cost of my rig.

We'll need to see it it's compatible, but it sounds like you've fallen for marketing hype if you NEED a 64-bit OS. - to run in 64-bit mode, you need a G5. - the advantages of 64-bit mode aren't really relevant to most applications On the other hand, Tiger has some neat new features, even on 32 bit systems. I know I'll be trying it as soon as it ships.

I've also pre-ordered it and will test it as soon as I get it on my spare drive. I'm a sucker for this stuff

Well, never mind the 64 bit thing, all I can see is Digidesign didn't post anything on their site regarding this point. I remember that even before the release of Mac OS Panther, there was a message saying that a ProTools upgrade would be necessary in order to use Panther. Nothing this time. Hope it means that it will work and there's no point in worrying.