Senator Mel Martinez won't seek re-election in 2010 (mind the door)
Senator Mel Martinez will not seek re-election in 2010, and might even leave before his term is up, according to this. According to this, a Jeb Bush spokesman says that Governor Bush has not given serious consideration to running for the U.S. Senate, or any other office at this point, which probably means the opposite.
As for Martinez, despite being from Cuba he was a strong supporter of basically allowing Mexican citizens to enter the U.S. at will. He spoke out in support of amnesty several times, and in 2007 he quit as RNC chairman. Expect him to obtain some sort of part- or full-time sinecure somewhere and use it to push the general Bush agenda, specifically focusing on "comprehensive immigration reform".
Summary: good riddance.
UPDATE: Now, a source says Jeb Bush is considering a Senate run.