You don't want to get such an expensive motherboard if you're not overclocking; that defeats the purpose of a Z77 motherboard.
Here's what I'd recommend.
Get an i5 3470 because SC2 is an extremely CPU intensive game, and you'll want a better CPU than GPU. The GPU doesn't matter as much.http://www.microcenter.com/product/400664/Core_i5_3470_32GHz_LGA_1155_Boxed_Processor
Then, get this motherboard, which has most of the features of the Z77 with the exception of overclocking.http://www.amazon.com/dp/B008KW62WK/?tag=pcpapi-20
Then, with the extra 100 bucks, he could go with this GPU (including mail in rebate) if he wants to play some BF3, or something like that later on.http://www.newegg.com/Product/Product.aspx?Item=N82E16814150598&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-na-_-na-_-na&AID=10446076&PID=3938566&SID=
If he's sticking with SC2, then this GPU should be sufficient.http://www.newegg.com/Product/Product.aspx?Item=N82E16814121472&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-na-_-na-_-na&AID=10446076&PID=3938566&SID=
It's 80 dollars with the mail in rebate.