ok its not ALL math, it is personal preference as well but heres what i did..
i went thru album by album listening to clips of the songs and slotted them into "tiers" (Best, Good and "skip") based on how i felt about the song while listening to it. so listening pleasure had to do with this part. then that gave me a percentage of songs from each album that got slotted into each tier. after doing this, i rated every song out of 10 in each tier. for example, all songs in "best" scored an 8 or better. a lot of the time i did this by rating some songs and based listening preference off of one another to decide how to rate each. but i took the total score earned of all the songs and divided it by the total possible points and that got me an overall score of all the song ratings. three of the cds came out to 8/10 so i used personal preference together with how many really enjoyable songs i had ranked and that broke the tie. now i know my "best to worst" list for sure.