I was on the search for a pair of pc speakers. Listened to the audio engine a2 and a5. liked them both and bought the a2. was blown away by the quality and volume of the sound from such small minimalist speakers.
Then I discovered true active studio speakers. Powered speakers, especially the a2's I have found, are very muddy in the sound they project. What seems like unbelievable bass is just distortion covering up other frequencies. I went looking for altenatives. Adam audio's old A5's were ok but I like krk's vxt 4. Both are small and unobstrusive and should sound more accurate than the audioengines. The best thing to do would be to buy as many as you can online, from vendors which offer 30 day return policies and test out yourself. If you are in the states, you are spoiled for choice, if not, I know how you feel. Despite what I or anyone says, the best thing for you to do is hear them for yourself.
Also try soundonsound website for reviews on the studio monitors. Very good info there.
Good luck.
Ps You should probably spend more on the speakers than the soundcard for greater results.