Logic 8 crashing on Mac book Pro

Question

I recently updated from Logic 7.2 to Logic 8. I created a brand new session (using empty template) and added 4 external Midi tracks and 2 Software instrument tracks (reFx vanguard & Nexus). As soon as I start running the session, it crashes the OS almost within first 3 - 5 minutes. I ran several processor intensive sessions with no problem what so ever in Logic 7.2. All of my other apps (Ableton Live, Pro Tools LE 7.4, Reason 4) runs flawlessly.
I read thru the message boards and so far has performed the following trouble shooting tasks with no success.
1) Repair disk and permissions.
2) Delete Logic preferences.
3) Created a new session without using a template.
4) Removed all the AU plug-ins from component folder and ran the session.
5) Selected different outputs for Logic in my Audio Midi settings.
6) Changed the buffer size from 256 - 512 and vice versa.
7) Captured the PID of logic app in activity window and ran a script to move it up in "priority".
8) Monitored the CPUs and disk usage ... the max it went up to was 53%, before the OS crashed. I also noticed that one CPU was been utilized a lot more than the other one.
9) Did a memory allocation task from Logic's Project Information page.
10) Have the latest Core Audio and Rewire drivers installed.
Short of doing an un-install and re-install of the app. I have tried whatever I could find as a proposed solution by people encountering similar scenarios as I am. Any help in this matter will be greatly appreciated!

Answer 1

Eventhough, 2 third party plug-ins shouldn't crash the OS, I will also try to run just the Logic native plug-ins and see how the session behaves.
'Shouldn't' is the operative word here. There have been a lot of posts in regards to Logic and other 3rd party plug-ins not playing nice. Just for experiments sake it's worth a shot. At least then you can start narrowing down the problem.
The pro app update that comes to mind is the ProKit 4.5. There were some other things recently but I don't remember specifics.
They all should come up in System Updates, so if you've run and nothing comes up than you should have the latest.