My computer setup...

...which is vastly better than my big rig

Anyway, here goes.

Dell 530 Inspiron PC
90 gigs of iTunes with recommended settings, etc.
Locus Design Axis USB Cable
Benchmark DAC1 USB
Kimber Select 1036 interconnects
Mackie HR824 mkii speakers
PS Audio Quintet w/ PS Audio AC-10 power cord
Furutech power cords on all other gear

I have to tell you; I'm genuinely pleased with this system, especially relative to cost.

The USB cable upgrade made an enormous difference over the $45 Kimber version (far more musicality and precision with the Axis. I maybe even should have gone with the $1100 Nucleus cable).

I've always been a Kimber Select fan, and my (admittedly spotty) aural memory tells me that all my systems have sounded better with Kimber wiring. What can I say? My gear and my ear, right?

Benchmark seems to provide a good price-performance ratio. Their claims of eliminating USB jitter hold some water from my personal experience, and the volume control is a nice option. An open, fluid type of sound that *hopefully* is just passing through on the way to the Mackies.

I chose powered speakers because I really didn't want to pay for an integrated amp when I'm just using one USB input. The 824 mkii's live up to everything that I've read and heard in other people systems, namely silky highs and good low end impact as monitors go (37 Hz).

Using the Furutech cords added in some low end thump and helped with imaging (i.e., a more three dimensional, less flat sound than with stock cords).

In the end, I've dropped less than $6,000 including everything on this system, and I find the results immensely satisfying.

Now if I could just find a way to burn those DVD-A and SACDs into the computer, I'd REALLY be in heaven. ;-)
You can use this HD plugin with Winamp for playback if you like, after you convert to flac or Wav.

Here's the DVDA ripper for Mac heads
DVDAExplorer for Mac.
Can you share your iTune's "recommended setting"?

I am not using Benchmark volume control, instead I control volume using computer. Don't notice any significant detail loss this way, but I use that setup for background music only.

So Kimber USB is no good? I am still using (free) USB cable.
My understanding is that all volume leading into the Benchmark should be at 100%. This includes iTunes volume and any computer-specific volume settings in your Control Panel/bottom toolbar. This was gleaned from a conversation I had with Benchmark personnel.

I thought the Kimber USB was so-so. Something of an upgrade over stock USB, but not great. The Locus, on the other hand, is better than the Kimber by several orders of magnitude. YMMV, of course, and there are those who thoroughly enjoy other USB options like Ridge Street and others.
I do have volume set at maximum on iTune and PC when I have it hooked up to my main system. when playing background music, Benchmark sits too far away from me so I use computer to adjust volume instead.

Thanks for the tips on Locus USB cable