I think the best way to organise is what suits you. I know a lot of people let the digital files stay where they fall. Because I started scanning film before I got the Sony, I looked at what I photographed the most. I too have a folder called Photography and under that is Film and Digital. Under those is simply People/Animals, Landscapes, Nature and Miscellaneous. The Film folder also has a Leica sub-folder because I wanted to identify what I shot on an antique.
I obviously starting naming scanned film and I saw no reason to change with the files from the Sony. I've only taken 2,500 shots with that over five years and kept far, far less. I can afford to name (and I remember most of them without having to refer to Bridge). I know my way means a small number of folders with hundreds of files, but the other way is hundreds of folders with a handful of files. I don't get calling a folder by the date - unless it is a very significant date, it would mean nothing to me.
Some people go berserk with keywords and I think for those who shoot professionally then there is a great need to be organised. I always do rough location (South East, Peak District, Peru) and then whatever I can see in the image that has meaning. I pinched some keywords off an internet site (abstract, transportation, religion, architecture etc.) and they work very well. I use smart collections in Bridge so I can look at just our wildlife, or the pets, or a particular holiday. I tend to mark up those for editing in advance and I use labels for editing, deletion, revisit, rescan, but they are always removed when I no longer need them. Bridge allows you to filter by so many things like colour profile, lens, exposure and the choices are almost endless. I hide the DNG files within the collections because I don't want to see them.
I save the RAW (converted to DNG) with the PSD together in the appropriate folder. Some time ago different versions crept in because I couldn't make up my mind which I preferred. I pruned those out a few months ago, but I do allow myself a second file as a black and white conversion. Very rarely I need a Part 1 and Part 2 if I want to use Topaz - it falls over with my enormous files, so I have to flatten if I want to use it. I never save JPG files unless I put them in here and that file goes in a folder for desktop background images.
So far, all my files from the Sony and the film scanned so far has almost filled a 300Gb external drive so I think I am working with far less than you, or indeed anyone in here. I think I will buy a 2Tb replacement and that should keep me going for a few more years. In theory my entire collection will always fit easily on a single drive (that is available at that time), so I don't have the bother of splitting. I believe Bridge can't cope with organising across more than one drive, where the LR organiser can. I've never used the latter, so I'm not sure, but it may be more help to you with multiple drives