Boxer will beat him.
California suffers from two basic problems. Liberal governance and an illegal invasion abetted by both major parties. Which problem is more sever is a matter of personal opinion but most conservative Californians will agree it is one or the other. Taken in that light here are the answers:
1) Boxer is a nationally recognized champion of liberal governance.
2) Marin is a long time champion of the forces and philosophies that are abetting the illegal invasion.
3) Casey is a recently transformed Democrat who has a pair of gilded, Clinton kneepads in her possession.
4) Jones is instinctively a moderate with conservative roots. Jones is a seasoned politician and he will compromise even those issues held close by his constituents.
5) Kaloogian is a core conservative. A member of the "far right" as described by his party which has drifted away from him.
For conservatives their are but two choices. Kaloogian or Jones. Republican pragmatists will probably choose Jones. The members of the vast right wing conspiracy will probably choose Kaloogian.
Regardless of your choice, one thing is certain. Within 3 weeks of the election, Republican loyalists will be sent out by the RNC to convince forum members that Marin is the "only sensible choice". These halls will echo with the mantra "If you don't vote for Marin you are voting for Boxer"