Interesting read. I follow a convention similar to Mouser and put extensive effort into filenaming. I avoid Default Permit (installs or otherwise) like the plague, for instance, anything to do with security is in its own dir structure on the C drive with an unusual name. My drives are partitioned with essentials only on the C drive (after 5-6 years an Image Backup is still only one DVD). Data is on the D Drive, nonessential programs on the P drive, Swap or page files on the S drive on Drive1 etc.
IMHO a good partitioning strategy is as important as file and dir naming conventions, esp keeping your C drive as tight as possible. That said, never have found the perfect strategies
Downloads go into a temp folder 1Dnlds on C along with all info/data pertinent to the download. It's then named and moved to my archive drive partition under a dir structure that's logical to me, for instance, W:\System\Tweak\TweakUI.zip or whatever the case. I use short names, and never use spaces preferring leading case or underscores and sometimes dashes.
I use the My Documents structure as a temporary drop folder when convenient, after which I move the files into my own MyDocs folder. It's organized simply, eg, Pics/Smilies, Docs/Humour etc and file type does not have a bearing. I have 6 partitions on Drive0 and 3 partitions on Drive1. My backup routine sweeps all partitions and puts 1+ copies on drive M (for mgmt), one copy is an exact replication, the + copy is for info I want to keep duplicate copies (not much) and is under a time stamp dir name.
The 8 partitions (not C) are mirrored on 2 180MB USB Hard drives during backup. I don't use indexing nor Windows Search (ugh!), rather I prefer searching if necessary. I like Agent Ransack as a freeware search util but use the Pro version on my main machine.
Some great food for thot in this thread, thanks to all who contributed