I owned a pair of AR-3 bookshelves back in the old days. Now I pretty much stick to "el cheapos" at home, very much on purpose ... if a mix I bring home sounds good over my Best Buy, mediocre system, it's generally going to sound 'killer' over BAD's system.
Actually I run JBL down all the time, but I do a good deal of mixing over a pair of JBL, self powered, near field monitors ... they're a good reality check. We also have a pair of high end Nova Audio's near fields sitting next to the JBL's on the console, which we were given to _audition_ a while back... I don't want to give them back, and may not. :)
In the studio, it is not so much the quality/cost of the monitor as the ability of the mix engineer to make the mix "translate" to the outside world's speakers over whatever he/she is using ... that comes more with an ongoing familiarity with a particular speaker, than with the quality of same. It's a real subjective thing, which is why some of us fly around with our favorite near field's in a flight case.
Just about any engineer worth his salt will tell you that the toughest part is getting the bottom end of a mix right, so you don't want too little, or too much bottom in your studio monitors, or you'll have too much or too little, respectively, in your mixes.
Many an album as been mixed over those little $100 Auratones I was talking about, or the old Yamaha NS10's with a piece of Kleenex over the tweeter to get rid of the harshness ... someone even marketed a tissue holder for the damn things at one point years ago. The ironic part is that some folks then spend literally tens of thousands to play those very same mixes back at home. :)
Audiophiles are some of the most practiced snobs around, worse in some ways than wine snobs ... well ... maybe not! ;>)