I can speak for Alesis M1 (passives, not actives - you can get them for about $200 plus what you spend on an amp) and Wharfedale Diamond Pro 8.1's.
The Alesis sound like good listening speakers. I always had problems getting mixes to translate, because bad mixes sounded good on them. Then I got the Wharfedales. The Wharfes (to me) are like the stories I read of NS10's: if it sounds good on them, it will sound good anywhere (and it's hard to sound good on them).
I use them both now. Certain flaws in the mix pop out better on each set. It's easier to hear overall spectral balance on the Wharfes, but I hear WAY more detail on the Alesis. I'd hate to be stuck with either by themselves, but if I had to choose one I'd go with the Wharfedales.
Not sure this helps you, because I think the net result is that cheap monitors will likely be flawed in some way. If I were going with another set of cheap monitors, I'd probably take a look at the Wharfedale 8.2's or the Yorkville's.