I run DJ shows with equipment in the pro audio level.
This is what I'm currently running in my studio to simulate what I am hearing on stage before performances.
DragonFly Red USB DAC; $200
JitterBug USB filter; $60
Klipsch ProMedia 2.1 THX speakers; $150
ZMX122FX - Mixer; $120
Livewire Elite Interconnect Y-Cable 3.5 mm TRS Male to 1/4" TS Male 9 ft. Black [x2]; $60
ProMedia 2.1 is extremely balanced, but it's like moonshine without the right technologies. Sounds like junk with onboard audio, and without proper tuning, you might as well not upgrade from your current speakers, because you're not really upgrading, you're just testing out different speakers.
The physical drivers and controllers on these speakers are only sampling or amplifying what's coming out from the source.
ProMedia 2.1 offers great, flat audio and smoothes out increased depth with the THX engine. Companions are slightly enhanced on their own, which are good for minimalists, but if you can do a subwoofer, get a subwoofer.
Some thoughts about the "upgrade" and price range you're staying in-
FLAC/WAV/320k versus 128k audio, it will all pretty much sound extremely similar on a generic sound card and decent speakers. So if you're using onboard audio or an X-fi and expect something night and day amazing, don't be too surprised. High-end audio sound cards don't offer the depth of quality DAC's. DragonFly Red will replace the soundcard and offer audio reprocessing (DAC), but not without spiking elements where a USB filter, mixer and quality wires are needed to tune for the final outputs.
Basically, moonshine, where the sun is the source of light and heat, and we see glimpses of the bigger picture when the Earth rotates at different angles.