Who holds executive privilege once Obama is president?

Private practice lawyers know that when an organizational client changes management, the privilege is controlled by the new managers -- which may have very different agendas than the prior management.  What will happen under the Obama administration when Congress issues subpoenas to investigate the Bush administration?  (One obvious focus of the investigations: the OLC memos.)  Will Obama be hesitant to undermine the office of the President?  Will he gladly help Congress?  Will he release all the OLC memos for public scrutiny? The NYT reports on the issue. Apparently, even after Harry Truman stepped down, he asserted executive privilege and fended off Congressional subpoenas.  I expect that Congress will push much harder this time around.