To answer my own questions, Flight 370 was a Boeing 777-200ER. See the "ER"? That means Extended Range. It has a range of 7,700 nautical miles (compared to the non-ER version with a range of 5,235 miles). The distance from Kuala Lumpur, where the flight originated, to Jerusalem (simply chosen as a place in Israel) is 4,729 miles - well within Flight 370's range of 7,700 miles. Note that the plane first flow north for a while before changing direction, so the overall flight would have been longer than 4,729 miles, which would have put it out of the range of a regular (non-ER) 777. Interesting that the plane that just happened to disappear was an Extended Range version (or are they simply more common? I don't know).
Also, the final northwest heading was towards the middle east, which aimed it squarely at a number of political / religious hotspots (Israel, Pakistan, Kashmir area, etc) where there are ongoing suicide attacks taking place on a daily basis (Pakistan at the moment). As for the plane actually reaching Israel, that's pretty much impossible. It would have had to have flown over Saudi Arabia / Iran to get there, and surely the unidentified plane would have been intercepted by one of those two countries. Then of course the Israelis would have shot it down for certain had it actually made it close to their border.