I'm wondering how you all get "map to sphere" to work without horible stretching. 
Two factors.
First, work in very high resolution - 4096^2 at least if you can manage it, and then you can scale down the end result if there's too much stretching to your tastes. Also, don't make the sphere fill the whole layer (distance 0.9) - keeping the sphere at default distance tends to reduce surface stretching notably. Of course the distance kinda also depends on whether you're making a skybox texture or a distant planet background image...
Secondly, to avoid polar distortions in the mapping process itself, you can negate them almost completely by applying Polar co-ordinate distortion to the texture's northern and southern hemispheric part and then blending them together with the unstretched equatorial area.
For example, a simple continental outline map could look like this (in 4096^2, of course):
Same technique applied in multiple layers to make a gas giant texture:
It takes some practice and manual labour to get the parts of the map to match, but in the end it isn't as complicated as one might think, but when you get it down, you can make pretty good spherically mappable textures with minimal distortion.
Also, you can cheat your way around polar issues by using large polar ice caps, but, well, if the planet is not supposed to have them you're kinda screwed.
