Looking for upgrade to desktop speaker

As the title suggested, I am using a computer with sound card (creative sound blaster titanium x-fi) and speaker is creative t40.

I have two options in mind. First is getting a better active speaker (like airpulse a100 or yamaha nx-n500). Second is a combination of desktop mini power amplifier and passive speaker (nothing in mind though). I think the second one provides me more flexibility in choosing as there are lots of passive speakers to choose from.

As I am not familiar with the second option, I would like to ask for some input for the pro and cons in doing so. Thank you.

Also, it will be nice to have some suggestions. The budget is about 600 USD.

I’ve got the Airpulse A100’s. Fantastic near fields. One thing you won’t find online about them is for whatever reason, the DSP on optical sometimes shits out when turning it on and it makes the speaker sound blown out. Turning them off/on again or switching inputs to/from fixes it. I’ve returned three pairs and still have this issue. The short amount of time I used USB and PC (RCA) in it didn’t have this issue. Other thing to note is the sub out sends full signal and doesn’t cut lower frequencies from the main speakers. Despite all of this, I love my set and the red is gorgeous.