To change the default font for Illustrator CS4
1. Choose File > Open and go to Documents and Settings/User/Application Data/Adobe/Adobe Illustrator CS4 Settings/New Document Profiles (Windows) or to Users/User/Library/Application Support/Adobe/Adobe Illustrator CS4/New Document Profiles (Mac OS).
2. Open one of the default document profile template files (Basic CMYK, Basic RGB, Mobile and Devices, Print, Video and Film, or Web, depending on which type of document you intend to use).
3. Choose Window > Type > Character Styles.
4. Select the Normal Character Style and choose Character Style Options from the palette menu.
5. Select Basic Character Formats and choose the desired font from the Font Family menu.
6. Click OK, and then choose File > Save and close the file.
7. Choose File > New and select the desired default document profile.
1. Choose File > Open and go to Documents and Settings/User/Application Data/Adobe/Adobe Illustrator CS4 Settings/New Document Profiles (Windows) or to Users/User/Library/Application Support/Adobe/Adobe Illustrator CS4/New Document Profiles (Mac OS).
2. Open one of the default document profile template files (Basic CMYK, Basic RGB, Mobile and Devices, Print, Video and Film, or Web, depending on which type of document you intend to use).
3. Choose Window > Type > Character Styles.
4. Select the Normal Character Style and choose Character Style Options from the palette menu.
5. Select Basic Character Formats and choose the desired font from the Font Family menu.
6. Click OK, and then choose File > Save and close the file.
7. Choose File > New and select the desired default document profile.