Probably Michigan (neutral site) or Washington (road home). And what great OOC giants have been slayed by Pac 12 / Big 12 teams?
Big 12 wins over "Power Conferences":
K-State 52-13 over 6-5 Miami
Texas 66-31 over 5-6 Ole Miss
Iowa State 9-6 over 4-7 Iowa
TCU 27-7 over 4-7 Virginia
West Virginia 31-21 over 4-7 Maryland
Pac 12:
Arizona 59-38 over 7-3 Oklahoma State (current #21 in BCS)
Arizona State 45-14 over 2-9 Illinois
UCLA 36-30 over 9-2 Nebraska (current #14 in BCS)
Oregon State 10-7 over 7-4 Wisconsin
Stanford 50-13 over 6-5 Duke
USC 42-29 over 6-5 Syracuse
Marquee game remaining: USC v. #1 ND
SEC:
LSU 41-3 over 7-3 Washington (current #25 in BCS)
Missouri 24-20 over 6-5 Arizona State
Alabama 41-14 over 8-3 Michigan (current #19 in BCS)
Tennessee 35-21 over 6-5 North Carolina State
Marquee games remaining: Florida v. #10 Florida State, South Carolina v. #11 Clemson
None of that is particularly impressive, IMO, but UCLA has the best win as of right now. We'll see how they compare after this weekend.