What is the best system &/or software for naming/numbering JPEG files & their folders of fine art photography?

With over 25,000 files (all JPEG), how do I proceed in renaming &/or numbering them (plus my new work) to make them easy to find? Currently I have most folders with general names like ‘Abstract 4.23.05’, “NYC 8.3.07”, etc., and the files within have also simple descriptive names (e.g. ‘sunset’, ‘Chinese landscape’, etc.)
Note: Right now I have Picassa & Adobe Elements and am considering purchasing either Aperture or Lightroom.