I would go for a i5 2500 if u can swing it, so much more oomph available to it, the 2400 little less, 2300 even less. Asus make solid boards but tend to be a little $ compared to competition, whomever you decide to go for a Z68 based board is the best option, although a GTX550 is newer then GTX460 1gb 336 shader core, I would go for a 460, they are more powerfull on average, and about same price, however
ASUS GeForce GTX 550 Ti DC Top 975MHZ 1GB 4.1GHZ GDDR5 DVI HDMI VGA PCI-E Video Card - DirectCanada this might be a good pick, and is a really fair $. Power supply up to you, I would get one that has around 52a available, at least you know there is headroom then, but to each ther own opinions.