Improving soil "in place"

During my years of ignorance (which has slightly abated from reading DG) , I thought topsoil was "the best" for growing anything. I am going to replant areas out front that I had blessed with a huge dump of topsoil many years ago. I am surprised anything ever grew in it! It is so dense and soggy even though there has been no appreciable rain for a couple of weeks... I've dug down about 2 feet (it goes deeper) and hauled what I removed to spread out back.

What can I add and mix a bit (the less work the better) that will give me a plantable area next Spring? So it drains and roots don't suffocate? From working in other areas of my yard that were never subjected to my black thumb, I am developing an appreciation of the phrase "moist and well drained". That's what I want, and/or loamy would be good.

I'm thinking sand and mini pine bark nuggets? Grass clippings from a last pass on the lawn?

Leaves, pine straw, grass clippings, manure. That is the mix I swear by. Layer it up, let it settle, layer on some more. By April, you will have some good dirt and happy earthworms.

Lots of information shows that composting in place is no better than double-digging in a load of compost. The earthworms will COMPLETELY exchange the top foot or so of material over 5 years, apparently, and they drag nutrients down into the soil in places you would never reach with a tiller.

Here is a picture of my Giant Lasagna Bed -- or actually 1/3 of it. 3000 sf of stacked leaves, pine straw, horse manure, and some shredded shrubbery.

I always start over and move plants and add compost. Wood chips and sawdust to build soil and then move plants back in after the soil has been ammmended. Top dressing is a good way but I feel it takes a long time to make soil only a little more structured. http://davesgarden.com/forums/t/591985/ This is how I did my old topsoil only bed.