TwoSix
Everyone's literal second-favorite poster
I like the Great Wheel, but I've mixed it around a fair amount. I've made the gods explicitly the side of "Law", and the primordials the side of "Chaos". Thus, divine magic is also "Lawful", and I defined arcane magic as explicitly "Chaotic". The Feywild is the areas where the Material Plane and the Chaotic planes blend together, and the Shadowfell is the transition area between the Material and the Lawful planes, where souls travel to meet the Gods, and the River Styx can be found. (I'm a big fan of Moorcock's Middlemarchthe from the Von Bek books, and I like the idea of shaded transitions between the real world and the immortal one.)The inner plane/outer plane distinction I can handle, and have used in my own (Rolemaster) games. But I have no real use for a seperate Astral and Ethereal plane.
As for the outer planes, I've treated them 4e style well before 4e started too, because the "wheel" makes no sense once you get rid of alignment - and then you can go for various sorts of thematic and pantheonic outer planes rather than the weird scattering of pantheons over planes that we've seen ever since the original DDG and the MotP.
Additionally, Limbo is the Elemental Chaos, and Nirvana is the Astral Sea, an ocean of stars where all Platonic ideals are crystallized islands.