Yeah I am the same, but I make playlists like angry, calm etc. No not really haha, I am a techno freak so my music is either very fast, fast or not so fast paced haha.
I don't use iTunes but I don't use any Rating system in any media player, especially WMP.
Simply put, if it's crap I delete it. My most popular music I move from my storage drive, where I moved the 'My Music' default folder to, and put it in 'Public Music' where I load music for my mobile device I plug into my cars sound system, instead of using discs.
Sometimes I will categorize songs in folders with a theme like 'Drive Fast', 'Mellow' or 'Wake Up", that kinda thing. 'Wake Up' being screaming metal...you get the idea. ;)
I only started using iTunes when I got my first iPod (a touch) this January. Since then I have added a little over 900 songs, and all but a bit less than 200 are rated. I have a smart playlist titled "Unrated", which automatically finds all unrated songs, and whenever I'm in the mood I listen to it and rate the songs as I go.
I find rating to be really useful. Especially when combined with the default "Top Rated" playlist from time to time.