Do you want 2.1, or Surround (5.1/7.1)?
I strongly recommend a 2.1 setup for two reasons:
1) Placement of surround can be very difficult not to mention the wires, and
2) A 2.1 setup for the same price will have better individual speakers. I'd rather have a great 2.1 system than a medium quality 5.1.
Alternate:
I have the STEREO (2.0 so no subwoofer) speakers; the M-Audio AV40's. While there's no sub they have 4" drivers which give a lot of bass. Not as much bass as a quality subwoofer but the advantage is there's far, far less sound transmitted to the floor below which a subwoofer vibrates directly. Also, for the price they may be better quality overall aside from slightly reduced bass.
I think the AV40's are still available.
Speakers:
Not sure of your budget but it sounds like you don't want to spend a lot so maybe THESE:
http://www.ncix.com/detail/edifier-m3300sf-2-1-speaker-set-a2-46891-1031.htm
Points:
1) Make sure customer reviews are good
2) Look up a review online as well
3) Make sure the Inputs and Outputs you want are there:
- stereo and/or digital for input from PC
- headphone output?
- auxiliary input? (for iPad or whatever)
- ON/OFF switch? (don't get one with the power switch on the subwoofer as it's a pain to access and it can waste a lot of power or just act as an unwanted heater)