I bought a Lenovo ideapad y570 laptop in August and I have been extremely happy with it.
Lenovo is known for their Thinkpad line of laptops which are for the business types. However, the ideapads are a really great line of consumer products that perform extremely well for their price point. The model I have is not available anymore (which has lower specs than the ones currently for sale), but I can run pretty much any game at decent details settings. I have no question that this laptop will be able to handle Diable 3 with ease.
Currently, there is a very nice sale on the whole Y-series line. Here is the link:
http://shop.lenovo.com/SEUILibrary/c...EC3E976E7F7028
The most expensive one listed there has an SSD drive in it, which will make your comp super responsive. The graphics cards, the Nvidia GT 555m is one of the best mobile graphics cards out there.
I really do highly recommend this laptop. If you are looking for a smaller model, the y470 is a very similar computer to the y570. There is also great deals on the y470 model right now.
Any questions about my experience just ask, I'll be happy to answer them.