The problem with desktop speakers is that nobody has invented a way to produce good quality bass in a small enclosure. Any solution will, necessarily, be a major compromise in the bass department. The good news is that, given your price range, you have three excellent compromises available:
1) The Focal XS-1 is a 2.1 system which includes really excellent iPod/iPhone compatibility, and tiny desktop modules. It looks gorgeous. It has serious amplification built in. You can easily blast your head off. Focal makes their own speaker cones, so this is not cheap stuff.(It also includes USB audio in.) The compromise: they use a subwoofer. In my brief audition, they sounded a bit harsh and strident (i.e. too much emphasis on high frequencies, bordering on distortions). If I were buying them, I'd spend a lot of time burning them in to see if that cleared up. If not, I'd be returning them.
2) The B&W MM-1 has no iPhone/iPod stuff, but does include USB audio in. They do not even have a subwoofer, so their compromise is that they do very fancy digital signal processing to produce better bass response. Audiophiles sneer at this kind of shenanigans. But the kernel of truth is that DSP can give you headaches or just "sound fake." I listened to them for a few hours, and was impressed, though. Amazing imaging. I didn't hear anything terrible sounding -- but this is something you'll have to pay attention to.
3) You can find an amplifier and buy some used passive studio monitor speakers, such as my favorites, the Tannoy System 600. These use a unique and wonderful six-inch "dual-concentric" driver, where the tweeter is inside the woofer. The same driver is also in their NFM-6 speakers. (The System 600A is the same speaker with an amplifier bolted to the back. They sell for a LOT more.) Tannoy also makes an 8" dual-concentric driver in their System 800 and NFM8 speakers. (Tannoy also sells traditional woofer-tweeter-rectangle-box speakers. I haven't listened to them, much.)
These have unbelievable sound in the near field listening configuration. I'm tempted to say "unbeatable." The compromise is that they are larger than you'd prefer -- and you'll have to scout a pair on eBay, which might take 3 months. But you can get an excellent amp AND the speakers for $500, with some left over. If you get REALLY REALLY lucky, you might score an amp that can bi-amp the Tannoys.
ANY of these choices is likely to sound great to you, BUT: All three will sound very different from each other.
Given your writing, I'd suggest you follow these steps in order:
1) Buy the B&W MM-1 from a dealer which will give you a 30 or 60 day "in home trial." I bet that when you first listen to them, you will LOVE them. But you have to make a commitment to listen to them a LOT over the 30 days. If you find that the DSP they are doing is making your ears tired, or giving you annoyance, return them. If not: Keep 'em, and if some audiophile gives you grief, offer to dip their head in liquid nitrogen (kidding).
2) If you decide to try the Focals, buy them from a dealer which will give you a 30 or 60 day "in home trial," and ask them if they have a pair that has already been burned-in some, maybe a returned pair that's been inspected. (Some people listen for a week, decide they can't hear any difference from their $50 Logitech blasters.) In any case, listen to them, then set them up in a closet and run them 24/7 for a week or two to burn in. (You can use white noise, pink noise, or music to burn them in. I usually use internet streaming radio, especially trance, drum and bass, or techno music.) Then listen to them. Either you'll hate them outright, or you'll spend some fiddling with the sub, and then be very happy.
3) Obviously, if you are buying used Tannoy studio monitors, you can't return them if you don't like them, and you probably can't go listen to them in person before buying. So you'll have to make sure that they look "brand new" -- especially the drivers. They use a plastic cone attached with a rubber surround -- both must be perfect. They also have a metal "tulip" in the center. Very distinctive, so I've never seen fake Tannoys. (If someone's going to rip you off, they'll probably show you pictures that look perfect, but send you a pair with torn rubber surrounds. More rarely, they might have a pair that actually does look perfect, but has something burnt up inside.)
I've had excellent luck with these speakers, having bought about 5 pairs off eBay. All of them were perfect, and all sound fantastic.
Edited by haineux - 8/17/11 at 2:10pm
The A2 are a bit more sensitive to placement than the Focals. The Focals benefit from their integrated speaker stands ( the A2 must be propped up for best sound). The Focal XS comes with high quality cables, the setup will keep your desktop cleaner and tidier as the cables runs speaker to subwoofer instead of speaker to speaker. The A2 scales very nicely with any upgrade in DAC or cable, the Focals are not upgradable...
