Adobe Illustrator - Changing the Default Style in Illustrator (9/10.x)
When you first launch Illustrator, any object you create has a 1-point black stroke and a white fill. If this doesn't suit you, you can change this style to something else by updating the Default style in the Styles palette. To see how this works, draw a square that has the Attributes you desire, such as a square with no fill and a 2-point stroke. Then, [option]-drag ([Alt]-drag in Windows) the square onto the Default style (upper-left style) in the Styles palette. Then, just press the D key to apply it to any object you create. If you want to make the Default style change permanent, you need to do this in the CMYK and RGB Startup files; otherwise, it will only apply to the current document.