Former Bush aide Karl Rove, aka "The Teflon Turd Blossom", may be headed to a heapin' helpin' of legal troubles if he continues with his refusal to comply with the subpoena and testify before Congress.
"Executive Privilege" ends when you leave the White House, if you're the President. Of course, Rove wasn't the President, or even an elected official. He worked as an adviser to Bush, and his only out will be if Bush gives him a pardon before they hold him in contempt of Congress and jail him.
Bush may use a bunch of pardons between now and January 2009, but there's one pardon that won't help him because it doesn't exist; the pardon that will exclude George W. Bush from prosecution after he leaves office.
A President can't pardon yourself.