Brad,
I think we should file a bug report, but in the mean time make sure you add these repos to your apt:
x-org
deb
http://ppa.launchpad.net/xorg-edgers/ppa/ubuntu jaunty main
deb-src
http://ppa.launchpad.net/xorg-edgers/ppa/ubuntu jaunty main
Key for file (make blank text file and paste the stuff that begins below) then go in authentication tab in software sources (authentication tab, import file)).
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Version: SKS 1.0.10
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=ZVmk
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Nvidia 180.60
deb
http://ppa.launchpad.net/voria/archive/ubuntu jaunty main
deb-src
http://ppa.launchpad.net/voria/archive/ubuntu jaunty main
key for file
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: SKS 1.0.10
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compiz
deb
http://ppa.launchpad.net/compiz/ppa/ubuntu jaunty main
deb-src
http://ppa.launchpad.net/compiz/ppa/ubuntu jaunty main
key for file
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: SKS 1.0.10
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Than update the system.
Once you do that Ubuntu will generally run cleaner (no Firefox hangups) but Virtual Box will still misbehave.
Taras