I'm so starved for more CC, lulu and Code Geass in general that part of me wants to be ecstatic over this news but most of me is just dreading it. Like many of you have said, this anime was awesome as-is and it had a fantastic ending, with closure and opportunity for fans to specualte.
Another thing about the way they're bringing it back, is it's in manga form. I know many people prefer manga to anime, but one of the things about Code Geass that really impressed me was how absolutely beautiful the animation was and how awesomely the music was written. Now it's going to be black and white still frames on a page. Definite step down imo.
I'm sure part of me will love seeing some of the characters again in a familiar setting, but I guess I'll just have to wait and find out in 2010.