My favourite so far would be Ron Barcelo, but I haven't really tried hard to expand my horizons on the subject matter. Each time I go into "systembolaget" and look around I chicken out and buy the one I normally like. It's a bit to expensive to experiment and maybe not liking it. :/
My friends tried to get me to tag along on their little "dudes only weekends" where only straight booze was allowed, so I had to find something I liked. Whiskey isn't my cup of tea, vodka is a tad to boring, cognac is vile so rum it is.
I'll tell you this though, if I want to leave nasty presents for your friends, beer is my go to drink of choice.