Funny you should ask -- I was just pricing studio reference monitors and can tell you a little about those, if you're interested. Keep in mind that you and I might be looking for different things, but I'll tell you what I've been thinking just in case.
Tannoy Reveals were what I settled on before checking out an Aussie engineer-friend's setup. He's done a lot of work in London and while he does seem to have, em, issues with the populace, they (the issues) didn't stop him from fetishizing British gear. Listening to his B&W D-6-somethings nearly sold me on them. The lows are there, but they're not overpowering, which is what you need to mix, since your major attention goes toward getting the mids in correct proportion. (This is what people don't get about studio headphones -- they shouldn't have too much bass.)
Really expensive B&Ws look space-age but don't justify their higher cost. $500 will get you a little more mid, $1000, a few more highs. The difference is slight and, frankly, not worth the cost. The unexciting black-boxed mid-priced B&Ws ($265 apiece, if I remember) are the least sexy monitors I've ever seen -- but they do sound sweet.
I tend not to like active monitors because they seem to have an overly compressed? (overly eq'd? some unpleasantly unnatural) sound -- a cheap effect seems to be operating under the hood. Time was, every studio in New York had $2000 Genelecs for overheads and they all sounded fake. I don't like that -- I want flat response, open design, natural sound. Which is why I'm ditching my ancient trebly vintage-80s Yamaha NS-10Ms, if anyone's interested (here's a tip for you -- trust me -- don't be).
Oh, and just to add to the consensus: A Brooklyn-based producer/studio owner who used to hire me a lot (before I blew up at an incompetent client -- oops!) loved his Alesis monitors as well. He also had a pair of Tannoys but preferred the Alesis overall.