I hate small integral signs and thus I like ScriptLevel to be 0. I have set ScriptLevel to be 0 for Text cells, DisplayFormula, and InlineFormula. When in a text cell I press ctrl+( to create an inline math mode cell (for lack of better term). When I do this I notice in the option inspector that ScriptLevel is 1 and this causes a small integral sign to be typed.
In Mathematica 8 this did not happen. It was ScriptLevel 0. In Mathematica 9 is 1 and I haven't been able to figure how to change it to be 0 by default. I've noticed a number of odd behaviors changed in the new Default.nb and this seems to be one of them. I'm using OS X 10.7.2.
When using my notebooks created under Mathematica 8 I get the correct behavior. But not when using new notebooks created in Mathematica 9.