The only real advantage is the the ability to support two way x16 PCI-E. Other than that it would be hyperthreading (Useless in gaming and most tasks anyways) and triple channel RAM (As if 16gb is not enough). It is certainly cheaper and probably more worth your money. Assuming that you intend to spend less then $1000.
Here is a really nice combo:
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.519636I personally prefer MSI but I do some heavy overclocking. If you did the math, the motherboard is only about $100. This is actually a good thing as you shouldn't dish out too much on motherboards unless you absolutely need a specific feature.
Here's some RAM. And holy stuff, when I built my computer the cheapest DDR3 set was about $95. Ram won't do very much for you performance and most of it you will need to overclock it to the listed frequency anyways.
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231180
And finally the video card. The 470 is about the same as the 5850 performance wise. I should let you know that the 470 is more or less over-kill for your first system. I own the 460 and I was able to overclock almost 40% and it performs about the same as the 5850. If you chose to get the 460 make a topic or PM me if you want the run down on overclocking a GPU. (I linked to the 460) The 460 I chose is the EVGA model. EVGA has fantastic service and lifetime warranty. They also allow you send in the card if it doesn't perform as you thought and they will send you a 470 if you pay the difference.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814130562