Magento:: Shopping Cart grand total, subtotal, Discount

$quote = Mage::getSingleton('checkout/cart')->getQuote();

$grandTotal = $quote->getGrandTotal();

$subTotal =  $quote->getSubtotal();

    OR

$totals =  $quote->getTotals();

$subtotal = $totals["subtotal"]->getValue();

$Discount = $totals["discount"]->getValue();