The bigger and more conservative the majority the better. I am not a big fan of Boehner; I'd rather have Pence or Bachman or Ryan or no doubt others, but any R speaker would be a major step - a vital step - in stopping the destruction of the country.
It is vital, but probably less so that we have a cloture- proof majority in the Senate. If Obama gets to nominate another Justice, we cannot count on Snowe, Collins, Brown, Graham, and perhaps Lugar and McCain (have I overlooked any other?), so we need at least a 6 seat gain to keep the Supreme Court in play.
One can dream, but it does not seem possible to gain veto- proof majorities in either chamber, much less both.