Yes, a generic crossover filter is a great place to start when it comes to matching a set of drivers to your design, but that only adjusts the curve based on a generic slope and doesn't address how said slope interacts with the room. The Mini DSP is capable of doing both with the aid of REW or a similar type tool.
Another option is using the MiniDSP as a straight crossover AND adding an EQ overlay to fine tune the results. This accounts for all the multitude of reflections and interactions with the room. Here again, REW makes that relatively easy - I run several frequency sweeps and average those, add a generic "house curve" to the results, then create an output curve that imports directly to the "convolution kernel" included in jRiver's Media Center. After decades of scrwing around with EQ, can't say as I've felt the need to do much if any tweaking in the couple intervening years since I did that here.
Worth mentioning - if you haven't already done so, AND your room (and roommates allow it) you should also take this opportunity to adjust any major inconsistencies with traps, baffles and such for the best results. My room had a standing wave from hell at around 160hz and was pretty shrill at the top - I eventually was able to calm those problems down a LOT. After that, run some more sweeps to review the results and create another output file to compensate. Repeat as necessary.
PS - here's the "house curve" I used. Works wonders, as the average ear really doesn't like "flat".
http://www.brainfartz.com/images/Stereo Stuff/eq/Small Room X-Curve.txt
Also, it could take a bit of time to retrain yer brain after doing serious EQ, depending on how far off you were before. The real proof comes when you hit the bypass button and the music goes meh ...