Studio monitors are for exactly that, monitoring sound in a studio setting when recording/mixing music, for example. My questions on this subject are...
1) Do you just want a 2.0 (stereo) setup?
2) Do you want to add a subwoofer?
3) How do you plan on connecting studio monitors (depending on the type you want) to the source device e.g. a USB DAC or directly to the PC/sound card? 3.5" headphone cable? RCA white/red cables? Optical S/PDIF? Coaxial S/PDIF? HDMI? TRS? XLR?
4) Do you want a DAC built into the monitors + volume controls in the pair, or do you have a way to control these via a USB DAC or something like that?
Look, I'll get right to the point and say if you want something simple, easy and affordable to connect to a PC via on board audio or a sound card or a USB DAC then I have two suggestions for you that will blow any Logitech speakers out of the water (Google them or search Amazon for them).
M-Audio Studiophile AV 40 Active Studio Monitor Speakers
Behringer Speaker MS40 Digital 40-Watt Stereo Near Field Monitors
I personally and honestly would NOT recommend the M-Audio AV 40's. I had a pair that died on me within 6 months and I didn't bother replacing them or RMAing them. It's a common problem with those monitors sadly so they set broken in box in my storage. I bought the Behringer MS40's a year and a half ago as the replacement for the M-Audio AV 40's and I couldn't recommend them enough. I'm currently using them on a secondary PC but I'm HIGHLY considering bringing them back to my main PC as I personally love and prefer their "flatness".
What you could do is go into an electronics store like Best Buy and see if they have any monitors there to test and judge for yourself if you like them.