Ivybridge is just a die shrunk Sandybridge, no real difference. But yeh, if you build in a few months time may as well get the IB equivelant, as long as the price is similar.
Not a fan of ASrock, go for an ASUS instead. ASrock = budget brand.
Make sure you get the low profile vengeance ram to keep your CPU cooler options open.
Mechanical hard drives are way overpriced currently, i'd get a Crucial M4 SSD then add mechanical storage when prices return to normal.
Make sure you get the low profile vengeance ram to keep your CPU cooler options open.

As for Ivybridge, I was hoping that Sandybridge prices may drop a reasonable amount when Ivybridge is released and then still use an i5 2500K/2600K.