Quote from Magna:
I doubt Rumsfeld is going anywhere any time soon. One, he feels he's got unfinished business in Afghanistan and Iraq. Two, Condi Rice really coveted the job of Secretary of Defense, in fact word was that she told Bush that if it wasn't available then she was returning to Stanford (where she was Provost prior to her job as National Security Advisor). With Powell resigning it gave Bush an almost irresistible carrot to dangle in front of Condi, and my guess is that even so she would've held out if she had any indication that Rumsfeld's departure was imminent.