Vektor's lyrics are pretty interesting in my opinion, in addition to the kick ass music. They're progressive thrash. Can't say I know anything about folk.
i think the first thing you really need to do is completely devour the first 4 sabbath records, the first 4 metallica and everything by Judas Priest...
Retarded internet dweller logic : Recommend the 3 most popular, highest selling, and most overrated metal bands in existence to someone who already claims to be a metalhead.
typical metal forum poster logic: feel good about yourself while putting down bands that others like and most probably influenced everything you enjoy.