http://shop.lenovo.com/SEUILibrary/controller/e/web/LenovoPortal/en_US/catalog.workflow:category.details?action=init¤t-catalog-id=12F0696583E04D86B9B79B0FEC01C087¤t-category-id=C46D71ACFD7C4475B8E490358F8CA8C3
I would recommend the Lenovo Y400 and Y500 over the Y480 and Y580 for gaming. The 400/500 come standard with the NIVIDIA GeForce 650m with the capacity to SLI two of them. This is due to its "Ultrabay" which allows you to swap out the DVD drive for a Blu-Ray Reader/Writer, Extra Fan, Extra HDD or the prementioned Extra 650m.
The Y480/580 on the other hand have the 660m which bests the 650m by about 15%, but that pales in comparison with the the 650m SLI potential setup.
Most of the other specs are comparable. Check each one's product page for a more in depth comparison or shoot me a question if you can't find what you're looking for.
Cheers

FWI the sale ends Tomorrow, Wednesday 2/6/13. So grab it while you can!!!!!