our house is locked up like fort knoxx LOL. Well it was mostly for the dogs and the kids when they were younger (but now the kids know how to work the gate locks, we taught them).
What worked for us were these vertical bar gates that are extra tall by Summer that we bought at babies r us. They were about $60 a pop but totally worth it and are pressure mounted so no fiddling with any hardware. For our kitchen since it's an extra wide and angled opening we found an online store called Safe Beginnings that had a hinge mounted gate which could be installed at an angle and extended with additional pieces (also vertical bars). The vertical bars prevent the climbers from getting high.