After throwing an absolutely amazing surprise 30th birthday party for my girlfriend this weekend she has crumbled under the pressure and told me she is going to buy me my monitor speakers for my birthday (which is next month)! I'm pretty set on the idea of the KRK rokit 6's. But what I need to know is this..... Do they just plug directly into my PC? or will I need to buy a seperate amp? or soundcard? or anything for them to work? Or is it just a case of plugging them into the PC and hey presto?