If I'm not mistaken, I'm assuming you want all your points to be visible on the map with the highest possible zoom level. I accomplished this by initializing the zoom level of the map to 16(not sure if it's the highest possible zoom level on V3).
var map = new google.maps.Map(document.getElementById('map_canvas'), { zoom: 16
, center: marker_point
, mapTypeId: google.maps.MapTypeId.ROADMAP
});
Then after that I did the bounds stuff:
var bounds = new google.maps.LatLngBounds();
//you can have a loop here of all you marker points
//begin loop
bounds.extend(marker_point);
//end loop
map.fitBounds(bounds);
Result: Success!