If you want to remove the Checkout buttons from the top of your Magento Cart page, here are 2 ways to do this .

(1) Remove the checkout buttons using Layout XML.

<checkout_cart_index>
    <remove name="checkout.cart.top_methods" />
</checkout_cart_index>

(2) Just hide the buttons using CSS

.checkout-cart-index .title-buttons .checkout-types {display:none}

If you want to remove only Google Checkout and/or Paypal Express buttons from the top of the Magento Cart Page, you can use the following Layout XML

<checkout_cart_index>
    <reference name="checkout.cart.top_methods">
        <action method="unsetChild"><name>checkout.cart.methods.googlecheckout</name></action>
        <action method="unsetChild"><name>checkout.cart.methods.paypal_express</name></action>
    </reference>
</checkout_cart_index>

This post details how to fix a bug in Magento 1.4.* processing payments using PayPal Express. 

The problem occurs when a customer selects PayPal Express, makes payment on the PayPal site, and then completes the transaction on your Magento store. The error the customer sees is “This payment cannot be processed using your PayPal account at this time.”, however the payment is processed successfully and shows up in your PayPal account.

To fix this, open up app/code/core/Mage/Paypal/Controller/Express/Abstract.php and comment out some code in the placeOrderAction function

(For a cleaner fix, copy the file to app/code/local/Mage/Paypal/Controller/Express/Abstract.php and then make changes to the new file)

public function placeOrderAction()
{
    try {
 
        ....
 
//        if ($url = $this->_checkout->getRedirectUrl()) {
//            $this->getResponse()->setRedirect($url);
//            return;
//        }
 
        ...
    }
}

The response object from PayPal is returning this on the final placeOrder step:

[SUCCESSPAGEREDIRECTREQUESTED] => true

This means that the Magento store thinks it should redirect back to PayPal to finalize the order, however it does not need to redirect.

This fix has been tested on Magento 1.4.0.1, Magento 1.4.1.1

It has also been confirmed to work with PayPal Pro accounts (Both PayPal USA and PayPal Canada Pro Accounts)