neither are very good for gaming, if you're looking for a proper gaming laptop i suggest looking at the Asus Republic of Gamers line or an MSI, these give you the biggest bang for your buck and range from 800$ to 2000$. Make sure you read the reviews though, because some of the Asus models experience a lot of problems.
I personally bought the MSI GX640-260 (http://www.amazon.com/MSI-GX640-260-15-4-Inch-Gaming-La...), available for 1100$ and great for gaming.
To properly be able to game, the laptops you mentioned above are not that good, but they will be able to deliver a mediocre gaming experience. If you decide not to go for an Asus ROG or MSI, then I would choose between the Vaio and n61 based on price, appearance, battery life, and heat, because in performance they are basically the same (the Sony will deliver a slightly better experience but it would be practically unnoticeable, especially in games).