Jeff is right - get your organizational scheme down now before you've got thousands or tens of thousands of 20mb images to try to make order of later. K.I.S,S.
Let LR import into year/year-month-date format (2011/2011-10-20) and then immediately make a collection on every import. Leave the folders alone, they'll fend for themselves as you import. LR will be consistent with every folder name going forward, the key to finding stuff later.
When creating PSDs or HDR images, LR automatically places them adjacent to the originating RAW files. Leave them where they are created. Since they're associated with the original files, it is smart to keep them all together.
If you want to separate out your HDR images, create a collection for them. You can always add to the collection (by dragging them from the grid or filmstrip), and sub-divide into topic areas as your collection of HDRs increase in size.
Discipline is important in using Lightroom as an organizational tool. Always keyword. Always use the same file structure scheme on import. Always make collections and try to avoid moving images around in folders or renaming folders, especially OUTSIDE of Lightroom, behind its back. You can do all of that "moving and renaming" in Collections.