<select
         ng-model="colorModel"
         ng-change="updateColor(colorModel.id)"
         ng-options="i.label for i in colorOptions">
</select>

$scope.colorOptions = [
        {value: 'red', label: 'Red', id: 0},
        {value: 'green', label: 'Green', id: 1},
        {value: 'blue', label: 'Blue', id: 2},
        {value: 'yellow',  label: 'Yellow', id: 3}
    ];

//setting it here works just fine
$scope.colorModel = $scope.colorOptions[2];


$scope.nextOption = function(){
      $scope.groupIndex++;
      $scope.currentOption = userOptions[$scope.groupIndex];
      $scope.colorModel = $scope.colorOptions[$scope.currentOption.colorID];
      //I event tried this with no luck
      $scope['colorModel'] = $scope.currentOption.colorID;
}

<select
         ng-model="colorModel"
         ng-change="updateColor(colorModel.id)"
         ng-options="i as i.label for i in colorOptions">
</select>