Q:

How do you get the balance of an account using truffle/ether-pudding?

Is there an ether-pudding way to get the balance of a contract/account, or should I just use web3.eth.getBalance(account)?

A:

This doesn't exist in truffle-contract. Here's a quick way to wrap web3 calls to make them use promises.
const promisify = (inner) =>
  new Promise((resolve, reject) =>
    inner((err, res) => {
      if (err) { reject(err) }
      resolve(res);
    })
  );

const getBalance = (account, at) =>
  promisify(cb => web3.eth.getBalance(account, at, cb));

// use getBalance
const bigNumberBalance = await getBalance('0xabcdef');
console.log(bigNumberBalance.toString());

You can use this promisify helper to wrap any function which accepts a callback param and handles errors the same way as web3. Here's another example of using it:
const getTransaction = (hash) =>
  promisify(cb => web3.eth.getTransaction(hash, cb));

// use getTransaction
const transaction = await getTransaction('0xcaff');

A:

Unless something has changed in ether-pudding, it is primarily focused on wrapping/simplifying contract code while also adding javascript promises to deal with asynchronous calls.  So I do not believe it has a simpler call to get the balance.
Short answer: use the web3 call you mention.

