Have 2 boys, both their first words were HOT! Both of them were brought near the stove to feel the heat and were given a stern and shocking (right to tears) HOT DO NOT TOUCH from me. At that point in their lives, they'd never heard a scolding like that (haven't since as a matter of fact). For a time after they would point at the stove and share with me their knowledge of the stove being hot by repeating it over and over. Neither come within 10 feet of the stove to this day and don't even play around it when it is cold.
With one kid at a time, keeping them away from the stove barring an accident wasn't a problem. With 2 kids around playing, the chance of an accident goes up regardless of how well they were taught. My kids are 3+ and 1+. We still don't have a gate and the wife and I keep debating whether to get one or not. Where our stove is located, the boys have no reason to play near it, and since they have been around it since day one, and have been taught better, have no reason to experiment since it is as familiar as the coffee table. However, an accident is the issue.
If you do get a gate, the concern that I have is I've seen some homes where the stove becomes "the forbidden fruit" and the kids wind up making another danger by trying to throw toys into this area, poke the stove w/ things, etc. First time that gate is left open you'll have a kid like this right in there finding out what hot means on his own. Depending on the stove's location, it is possible to keep things safe w/out a gate, but having one helps prevent what cannot be planned for (tripping over a toy on the floor).
Regardless, education about the stove and you bringing them near it when it is appropriate is a must. At the end of the day, do what makes you most comfortable but don't let it replace a healthy respect through education.
pen