The "ASUS P8Z77-V LGA" has 4 Sata 6gb/s ports & INTEL Lan chipset & Wireless Lan onboard
The "ASUS P8Z77-V LK LGA" has 2 Sata 6gb/s ports & the standard RealTek Lan chipset
The main reason the non-LK model costs more is the far higher-end LAN/WLAN chips by intel which are included (only found as standard very high-end motherboards, suhc as the Asus Maximus/Crosshair). The sata ports are trivial and unless you're running more than 2 SSDs off of your motherboard then you wont necessarily need the extra 6gb/s ports the non-LK models provide. If you/your roommate still need the extra 6gb/s ports then you'll have to either pony up the extra cash on the higher end model or find a non-Asus brand to go with (which I highly doubt since your friend here is dead-set on getting an Asus board.).
Asrock, made by ex-asus people. Good quality boards, and more robust features for cheaper. Just look at an unboxing to make sure it has all the cables you need (they are a tad chincy in that respect).