I like the idea of planes. But I've grown to dislike the idea of Great Wheel.
It lacks some feeling, some spark, some sense of wonder or just some uniqueness of belonning to some world not FR.
I liked first edition Manual of Planes. It was not that well written, and there was little actual useful data (only few passing minor mentions of plane's natural inhabitants and the like). It still was kind of idea mine for me, and helped me to realized possiblities of planar travel. I liked the idea that planes were deadly and not so welcomming to adventurers who hadn't come there to enjoy their afterlife or from kind invitation.
Then came Planescape. I disliked it instantly. There where some cool ideas yes, but it ruined whole concept of Concordant Opposition (yes stupid name), and re-placed it with Sigil. City of planes where 1st level adventurers can roam to be confused with stupid local word-twistings (the cant) and enjoy joining some white-wolf esque factions of this and that. You see, those kind of faction/order/tradition/clan/etc. ideas were awfully popular in those years of gaming, and they were awfully over-used, since I owned and played so many game systems. And I couldn't get over the language (which was cool too at those time, every white wolf game or Immortal for that manner did it, their own special language), and if they had just kept it within those in-character descriptions, I might have played it more.
3rd ed Book of Planes was cool, but futher reading reveiled it to be a bit too tidy to my tastes. They had removed some dangerous effects of planes, and no rules for spells working differently or anything. Planes of that book aren't that dangerous and unpredictable as they used to be. And there are some little things there I can't just feel to be like that. I consider it useful source material though, it's neat book after all.
Current planes I am using consist of sort of Elemental planes, that one can just walk to from certain special place from around world, or beings or those places can do the same, though it's rare for them wanting to remain.
Then there is the Beyond there all kind of demons come from. They are just referred as demons, though their nature vary. Any being of world can't be (normally) dragged there, so no-one knows what really is there, if anything.
Then there is astral/spirit world, but passing from there from spirit world of noermal world to spirit world of elemental planes and vice versa is again matter of finding entrance point. Magic can help creating those, but it's kind of radical, so more it's more common to use magic to transport/guide person to right kind of area.
Gods exist, but they don't have their own planes, and they don't offer afterlife.
They incarnate at will, but aren't really that agressive. They grant powers, and not just clerical to those that choose to follow them.
I used to use Wheel cosmology with my Greyhawk games, but it was mix of 1st edition and my own ideas. I am bored of it. Too bad it is new thing for my favourite dm. Because, though I like his adventures, his planar things just bore me mostly.