The OP disappeared from the thread a couple of pages ago, but I just picked up some M-Audio BX5a active monitors for my office setup today and I am very pleased with the results. I have been agonizing over the passive plus amp vs. active decision and just decided to give this a try. At $249 on sale at Guitar Center, it wasn't too big of a risk.
They are sitting on my desk, and are fed from either an iPod in a dock or my laptop in a bigger dock (s/pdif out), through my Headroom Desktop with Home Amp/DAC as a preamp. The speakers are bi-amped with 70 watts of internal power. One thing to note is that the inputs are studio-oriented, accepting either a mono TRS (tip-ring-sleeve, aka a 1/4" plug) or male XLR. I bought two mono cables with the male XLR on the speaker end and RCAs on the preamp end.
The sound is gorgeous and is actually better than I had anticipated--and better than the demo setup at GC. The clarity and crispness is exceptional, with the highs (especially) and mids sounding better than the deep lows so far. I think they need some time to stretch out, but I am also thinking about getting some of those Aurelex pad/risers to increase the bass performance. Right out of the box, however, they are quite good.
Somebody asked earlier about volume control and this is going to take some fiddling. For now, I have the speaker volume controls on about 7 and then I control the volume with the HR Desktop. However, when I am playing music from the laptop, there are multiple volume controls along the way: Real Player or Rhapsody plus the laptop's main volume control. I am not sure what is best, but for now I have those maxxed and just keep the HR Desktop in control. Any thoughts on this subject from experienced users would be appreciated, BTW.
All in all, I would recommend these speakers highly for a very simple and straightforward computer setup.