I finally figured out how to get a global system equalizer for OS X for free.
First thing is to install Soundflower which requires a restart. It’s similar to Audio Hijack Pro in the fact that it adds virtual sound devices but without any other capabilities like recording/sfx/etc (and it’s freeware).
Next you will need AU Lab from Apple. You can now download AU Lab standalone from the rest of XCode (you will need an Apple Developer Login though), go to the "downloads for developers" page and search for "AU Lab" to get it...and that’s it for software requirements!
Step 1) Change Audio Output Device
Change the output device in System Preferences --> Sound, choose the Output tab. You should see Soundflower (2ch) in the list of devices. Select that one.
Step 2) Open AU Lab
Easiest to search for it in Spotlight or it's default location is at
/Developer/Applications/Audio/AU Lab.app
Step 3) Setup Input and Output devices in AU Lab
You'll be prompted with "Document Configuration", use the Factory Configuration "Stereo In/Stereo Out". Change the Audio Input Device to "Soundflower (2ch)" and the Audio Output Device to "Built-in Output". Finally, click Create Document.
Step 4) Add EQ Effect
Under "Ouput 1" apply the effect Apple --> AUGraphicEQ
Step 5) Edit the EQ
Tweak like mad with 31 bands or change it to 10 bands to get an EQ that looks more like the iTunes one.
Step 6) Save your preset
The 3rd drop down from the left of the EQ window lets you save/change presets.
