Keep products in the wishlist after adding them to cart.

Here is an interesting question I found on the Magento forum:
Leave Wishlist as it is after adding item to shopping cart?

Here is what you can do.
Override the wishlist index controller (app/code/core/Mage/Wishlist/controllers/IndexController.php) or edit it if you don't care about keeping the core clean (I recommend to keep it clean though)
and inside the method cartAction() there is this line:

$item->addToCart($cart, true);

The second parameter of the method addToCart means 'Remove from wishlist'.
You can change the second parameter to false or remove it completely - it defaults to false.

Marius.