Looking for good computer speakers

Questions:

1. What is your budget.

2. Do you have any size constraints? (i.e., can you use a speaker that is 12" wide and 14" tall?).

3. Are you wanting to use the USB connection on the Mac?  Or do you have an analog output that you can use?

I am using an older model of Emotiva bookshelf type speakers for my iMac computer listening and am very pleased.  I am also using an Nuforce desktop amp along with a Schitt Modi.  Emotiva now has an updated model:  Airmotiv B1+.   Relatively inexpensive.  You might check the Crutchfield web site also to get a more comprehensive idea of what else is available. 

Want to listen to music. I would also like to use the usb connection. I like the idea of powered speakers with the dac built in, easy and all. As far a size goes, this is in a small outside office about 9' by 12'. 

HIGH END IDEA:

Pick your choice for a USB DAC/Preamp, such one of the following:

Used or "open box" Focusrite Clarett 2Pre on ebay for $285-300.  This is one of the best sounding pro audio interfaces for the money.  Company provides software drivers for Mac.

or

Audio-GD NFB-11.28 for $339-389 (depending on model chosen).  Excellent audiophile dac/pre.  NO Drivers needed for Mac OSX 10.6 (or higher).

Then buy a really nice set of powered studio monitors such as Yamaha HS-5 ($399 pair) or similar.  If you are willing to spend $800 and have the space, the Yamaha HS-8 are excellent and have a ton of bass.

LOW END IDEA:

If you want everything built into the powered monitors, including USB input, then you are pretty much limited to computer speakers such as Edifier, Bose or Logitech.  Edifier has their s3000pro for $800, but at this price you are going to get better results from the DAC/pre + Yamaha above.  The Edifier sounds a little flat/sterile in comparison; the Yamaha will end up being more "real" and natural sounding as well as more open sounding.  Check out Best Buy website or New Egg.

I have audioenfine hd3 and 5hd4.  Very happy with both.  Jerry