I'll add my name to the list of those who neither like nor use the Great Wheel cosmology. I find it too contrived and flat. The Planes become less a mythological inspiration and instead are just 'other worlds' for high level PCs to visit. I admit I have never been comfortable with the concept of Planes in D&D. Whilst I like some aspects, notably the Planes as a source of energy for magical effects in the world (the elemental and energy planes particularly), I find that their introduction seems to cheapen a DM's investment in his game world. By that I mean that as soon as the PCs can they seem to go plane-hopping, abandoning the carefully crafted world that they've adventured in up to then. To put it another way, as DM I've created a world with an interesting back-story, but that's left behind when the PCs hop off into the wide blue yonder. Can you imagine how, say, Midnight would feel, if the PCs get to just wander off and abandon its dark atmosphere when they got to high enough level?
That's why I've always had sef-contained and restrictive comsologies in all the D&D games I've DM'd for the last 15 years. The focus has always been on the Prime Material, with the other 'planes' being cosmological backstory.