Argh vespertine is so cool !! Coccoon was the first Bjork song I remember, it is so special. I saw a comment somewhere that it's so intimate that it feels like something we shouldn't be allowed to hear, like we're intruding.
Vespertine is hard to top imo, but every album has things you can really enjoy.
Homogenic definitely has the most interesting sounds and a very broad musical pallette (Hunter, Joga, Alarm call), makes me want to go to iceland feverishly.
Debut is very playful but has excessively beautiful and pretty moments (like someone in love, anchor song)
Post is wonderful too, and vulnicura feels wonderfully mature. It's all at your own leisure of course, hard to track down a direction with bjork hahaaa