Setting OpenLayers 3 Layer Visibility

Aragon, your answer pointed me in the right direction. Below is my final unclean code for adding layers to an array and then controling them.

In a javascript file I initialized the map and used a function to toggle visibility as follows:

//Layer array
var layersArray = [];

//Map view (Initial location)
var view = new ol.View2D({
// the view's initial state
center: ol.proj.transform([*Lat*,*Long*], 'EPSG:4326', 'EPSG:3857'),
zoom: 12
});

/*  Map Initialization  */
function initializeMap(){

var esribase = new ol.layer.Tile({
preload: Infinity,
  source: new ol.source.XYZ({
    url: 'http://server.arcgisonline.com/ArcGIS/rest/services/' +
        'World_Topo_Map/MapServer/tile/{z}/{y}/{x}'
  })
});

var poly1 = new ol.layer.Tile({
source: new ol.source.TileWMS({
  url: 'http://localhost:8080/geoserver/wms',
  params: {'LAYERS': '*Workspace*:*Layer*', 'TILED': true}
 })
}); 
poly1.setVisible(false);

var poly2 = new ol.layer.Tile({
source: new ol.source.TileWMS({
  url: 'http://localhost:8080/geoserver/wms',
  params: {'LAYERS': '*Workspace*:*Layer*', 'TILED': true}
 })
}); 
poly2.setVisible(false);

var poly3 = new ol.layer.Tile({
source: new ol.source.TileWMS({
  url: 'http://localhost:8080/geoserver/wms',
  params: {'LAYERS': '*Workspace*:*Layer*', 'TILED': true}
 })
}); 
poly3.setVisible(false);

layersArray.push(esribase); //0
layersArray.push(poly1); //1
layersArray.push(poly2); //2
layersArray.push(poly3);//3

var map = new ol.Map({
controls: ol.control.defaults().extend([
new ol.control.ScaleLine({
  units: ol.control.ScaleLineUnits.METRIC
})
]),
renderer: ol.RendererHint.CANVAS,
target: 'map',
layers: layersArray,

view:view
});
}

// Layer visibility function
function layerswitch(evt){
layersArray[evt.value].setVisible(evt.checked);
}

In the HTML I used simple checkboxes (example of poly1 toggle):

<input  style='cursor:pointer' type="checkbox" value="1" onclick="javascript:layerswitch(this)" class="Cpoly1" name="poly1check" id="poly1check"/><label id="poly1checkLabel" for="poly1check">Polygon 1 Layer Switcher</label>

you can find more information here under properties section.

visible     boolean | undefined     Visibility. Default is true (visible).

and live example in Layer group example.