Since you make no mention of other components, I'll assume you have none and recommend active monitors of some sort. Since you want to use a sub, make sure to choose ones with at least a line level output, or better a sub specific output.
I'm a big fan of the JBL lsr monitors. The new
lsr305 are ~$150 apiece right now, a screaming great value for what you get. On the down side, they only come in black, and they don't have a way to feed a sub, so that would need to be accommodated.
For something more plug and play, the
Audioengine A5+ does have all the convenience features you need, and they are available in very nice looking bamboo cabs, but the cost is more and the quality of sound for the dollar is probably not quite as good as with the JBLs (but the A5 are still a nice sounding speaker), and you would probably not have enough in your budget for a sub, at least not right away. Here is something similar from
Klipsch, just for another idea.
There are quite a few powered monitors to choose from. Hopefully this helps and I'm not off bass with my recommendation.
