I too was a very long time iTunes user... since the first Windows release until a few months ago when I got rid of my last iPod finally. I used it because I needed it for the most part to sync anything other than music on iPod touch, and I have a thing about installing more than one program that does the same thing. Asides from iTunes being a bloated clunky mess, there are other aspects I did like about it like how it's random play function worked.
So when I went searching for something more lightweight, that had all the features I otherwise cared anything about is how I came across MusicBee. If you like iTunes, but don't need advanced sync options for iPod touch/iPhone I really can't recommend it enough. The only thing that annoys me about MusicBee compared to iTunes... is if you select a specific track while in random, it kills the random and either stops playing or goes into album mode instead of reshuffling. The second thing that is more of a minor annoyance is the global hotkeys for things like previous/next and play/pause seem to be rather spotty and erratic when the player isn't in focus.
Like I did with iTunes, I use Rainmeter still for a persistent always on top now playing/mini player. I love that I can make it look however I want, and display what info I want to see.