Selections other than circles and squares?

I really need to know how to do triangles and subtract or add a diagonal selection. Quick mask isn't doing what I want it to do because the diagonal lines i make arent straight. Are there any other ways to do it? Am I doing something wrong? How is it done?

Thanks people.

In version 6 there is a preset triangle in the vector shapes.

But as far as making them freehanded, Just make your "grid" visible, make sure you have "snap to grid" selected. Then just use the polygon lasso to snap your selection to the grid in the shape of a triangle.

Perfect.. You made me feel dumb though :/

At least I got what I wanted..

Thanks :rolleyes: