Hardware Mounted Gates
Gates are essential once baby starts moving around the house. There are two basic types of gate on the market. The first type installs permanently with hard-ware into a doorframe or stair rail. Once properly secured to the doorjamb or wall with the supplied hardware, these gates are a safer choice for your baby. These needs drilling holes in the wood to install them. Many models are easy to remove from the mounting hardware when you want the doorway temporarily open. Consumer Reports suggests that this is the only safe alternative for use at the top of stairs, when properly installed and used. We agree with their conclusion.
Price range: $25 to $110.

Safety
The first place you'll want to install a baby gate, is at the top, and bottom of any stairway the baby may have access to. Gates installed at the top of stairways should always be done with hardware mountings, and not expandable pressure bars. This is to prevent when the bar can be jiggled loose and give way, allowing the baby to fall down the stairs. The pressure gates are suitable to be used at the bottom of stairs.
The model you choose, should have a flat top edge, to prevent injury when a child tries to climb over it and falls on the edge.

Kidco Beechwood Wall-Mounted Gate
This is a wall mounted swinging gate providing one handed operation. The gate swings both ways. Fits openings 26"- 42 3/4" wide and is 30" high. A little more expensive, probably due to the beechwood construction.

Kidco Safeway Gate
Highly recommended for use at the top of the stairs. This hardware mounted gate is very difficult to dislodge. It can also be attached to a banister or hollow walls by purchasing an installation kit for an extra $10. The vertical bar construction makes it unlikely that a child could climb over the gate.