Your half right Kevin. Those are active monitors, so no power amp is necessary, but taking a line out as opposed to a speaker out is definetly a good idea, if there is one. If there isn't, Gospel, make sure you turn the soundcard volume all the way down when you hook it up, and slowly and carefully turn it up when you get it connected and play back some music. A speaker level input into those active monitors could be a painful experience for both you and your monitors. Either way, consider getting something like a M-Audio Audiophile card to go with those. 1/8 inch outs are pretty much never connected to a good sounding D/A converter, and you'll gain a lot of recording and playback quality by spending the $150.
Also, with active monitors it's a good idea to have a physical fader between soundcard and speakers. Beware of software mixers that can end up blasting your actives at full mega volume when you least expect it.
Regards, RD