Someone with considerable executive, not just legislative, experience.  IIRC, Richardson was the only Democrat running who had any, and now he's dropped out.  Romney, Giuliani, and Huckabee have executive experience on the Republican side, though I don't favor any of those candidates. 

Unfortunately, the voters as usual seem too timid and risk-averse to reject all the current candidates and demand that the parties put forth really good candidates.

K Street and Big Money look like the only sure winners, yet again.