A better idea would be to post what you have heard. There are plenty of $400 bookshelf speakers out there.[/QUOTE]
Well, I have heard quite a few monitor/bookshelf speakers, but not many at $400 retail. I've auditioned the Usher V601, Kef IQ3, NHT 3, Vienna Haydn, B&W 683 and the Revel M12. These all cost more than the $400 Ushers, but the sound and looks of the little S-520 in piano black kept me coming back. All of the speakers had their strengths and weaknesses, but the little Usher was very hard to beat and less expensive too (the Haydn's were excellent, but 3x the price). I also planned to use a sub, so that was a factor. There really aren't many $400 speakers available unless you go to Bestbuy or internet direct. The Polk RTi series is a great bang for the buck as is the Infinity Beta. I have not heard any of the internet direct brands, but the S-520 seems to review favorably on the Ascend forum.
Also, some 4 ohm speakers can have a more stable load than 8 ohm speakers. The impedance swings on an 8 ohm speaker may dip lower than a 4 ohm speaker at certain frequencies. We're not talking about running a pair of maggies on a run of the mill receiver. I would bet money that the Dana 630 would work fine with most receivers in 2 channel (not a HTIB receiver).
I would also keep an eye on audiogon for some von shwiekert VR-1's which can be found for a little over your budget. Very nice speaker.
