Well, a Phenom II X4 Black Edition processor, 790FX motherboard and HD 4800 card would still hold up pretty well today. However, if you're looking into a new build, you might as well go with the Leo platform, unless the Dragon platform is enough.
and then ill get a 5770 or a 5850 i do have a amd phenom ii 955 3.2ghz
Dragon is still good to build or upgrade to but only if you already have the HD48XX.
If you are going to buy a motherboard, better get the 890 so you will have the future path to go Leo anyway. http://www.newegg.com/product/product.aspx?Item=N82E168...
It's a tad more expensive but what the heck, that is the reason why AMD conceived these Dragon/Leo platforming in the first place. To get people to build higher specs than actually needed.
PS: The MSI 790FX-GD70 is good board, I have one myself ( with unlocked X3 720BE & HD4890 - does that qualify as a dragon or just a false one? ).