[Ethereum] Explore local geth node with web3

I've just been trying to run the web3.eth.getBlock request as a test.

If I set my web3 provider to https://api.myetherapi.com/eth then the call is successful and returns the information about the block. However myetherapi has request limits so I figured I'd install geth and run my own node for this.

I installed geth and let it synch. Changed my web3 provider tocalhost http://localhost:8545 and I just get the following:

Unhandled rejection Error: Invalid JSON RPC response: "".

myetherapi set provider:

web3.setProvider(new web3.providers.HttpProvider('https://api.myetherapi.com/eth'));

local provider:

web3.setProvider(new web3.providers.HttpProvider('http://localhost:8545'));

Am I missing something key here? Thank you for the help.

var Web3 = require('web3');
var web3 = new Web3();
//not working provider.  returns the above error
web3.setProvider(new web3.providers.HttpProvider('http://localhost:8545'));


//this provider works but it is myetherapi with api limits.  
//web3.setProvider(new web3.providers.HttpProvider('https://api.myetherapi.com/eth'));
web3.eth.getBlock(5099447);