nVidia shut down their chipset division earlier in the year. Intel all but locked them out of their platform and since they pretty much burned their bridges with AMD when Core 2 emerged as the enthusiasts choice, AMD bought ATi and manoeuvred them into the position of primary chipset provider for their CPUs so nVidia had nothing really to go back to. It's not really that great a loss since, while better than most (including the AMD/ATi offerings), the nForce chipsets were never anything to really write home about, especially since for the last few years nVidia were mostly just rebranding and relaunching the 600-series chipsets they released in about 2006-2007.
Getting back to the topic at hand, you really don't want to be considering AMD at this point. Especially not in the price range you're looking at there. Even a dual core i3, which you can pick up for about USD$40-50 cheaper, will rape that Phenom more often than not all while using less power and emitting less heat. Even factoring in the slightly more expensive mobo, you still save about USD$20 (+/- $10 depending on whether ot not you choose to go for the
i3-540 and/or opting for the
H55 version of that board) and get a generally faster and more power efficient system if you go the Intel route:
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115222http://www.newegg.com/Product/Product.aspx?Item=N82E16813128430http://www.newegg.com/Product/Product.aspx?Item=N82E16820145251(It's actually slightly cheaper again than the last time I posted it, USD$316.97 vs USD$319.97 last time. Either way, still better than the USD$334.97 you're looking at for that AMD gear)
edit: Minor correction. After going back through the reviews, I seem to have confused the Phenom II with the Athlon II series. The 965 BE will outperform the i3-530, even in the single threaded stuff. HOWEVER, the margin is still too slim to justify the additional cost as well as the nearly double power consumption of the Phenom II.