How should i go about reflections in opengl?

As far as i know there are 2 ways,

1: "flip" the scene on the y axis and add some blending - Avoiding this since iv'e added deferred rendering, which doesn't support transparency without mixing with forward rendering.

2: render the scene to a cube map and do some stuff in the shaders - seems to be good for certain objects, but its a plane im trying to do reflections with.

any suggestions? Ive considered rendering the scene to an orthographic texture.