We have recently added on-page, mini shopping carts. They appear in the upper right and constantly update and remind the user of how much more he needs to spend to get to free shipping.
Question is, after they put an item in the cart, should they be taken to the old dedicated cart page? The pro on this is that the customer knows that something happened - ie they just successfully got the item in their cart. The con is that they can see this info on the item page anyway and it might dissuade them from buying more items.
I would work on what the customer expects. If they expect to be taken to the shopping cart (which is certainly my preference when shopping), then that's what you should do. I've shopped at places before that don't do that, and then you have to hunt around to find the mini-cart so you can check out. The more obvious the better, in my opinion.
If possible, I think a customer should remain on the same page, instead of being brought to a dedicated cart page as on your typical site. However, it needs to be obvious that the item was added. Additionally, the view cart and check out navigation needs to be clear when using this method.
Besides, the next thing you want them to do after throwing the items into a cart is to BUY THEM so the cart is the obvious place to be doing that from instead of making them search for the mini cart and find the 'checkout' button. yes yes... we want them to put MORE stuff in their cart first... but given the choice of no check out or a smaller order... well... so lets not even get into that. Another topic, another day.