This is a great thread. I've been engaged in (some might say fixated on) a similar hunt for at least a month, albeit with a hoped-for budget of around $300. I also listen to VBR MP3s and don't have a DAC or soundcard (don't think the Turtle Bay Micro Advantage I have used at home from time to time counts as it doesn't sound better than the headphone output from my dock, to my ears at least).
I currently have an old EV SonicXS 2.1 system attached to each of my work and home computers. They're ugly and, for dedicated computer speakers, big, but I love these guys - especially since I bought them for, IIRC, about $50 each from CompUSA when they were discontinued. Unfortunately, they're getting old - the volume controls are staticky, sometimes the RCA connectors have to be wiggled, sometimes they just don't work at all. So I decided it was time for a replacement. And, I hoped, a bit of an upgrade.
It's tough! I was first fixated those Cambridge Soundworks systems referred to above in this thread. But I didn't see many reviews or discussion anywhere, so I was cautious and backed away. Sounds like it was the right decision.
The Blue Sky Exo2 http://abluesky.com/products/exo2-new/
is a 2.1 monitor that sounded like a great fit. But street price doesn't seem to go below $425. I looked for a clearance or sale on the previous model, and actually thought I'd identified two at local Guitar Center stores for about $160 each, but they were defective.
I looked at the Aego M and also decided it sounded overpriced in the US. Also the control looks like it's on the sub, which would be inconvenient as it will go under my desk.
I then got started thinking about 2.0 systems and looking at powered monitors - none of which thrilled me because the footprints are generally too big for the space I have. I also looked at the Tweak City Gizmo/WAF-1 combination, because it sounded like a great deal. But again, those WAF-1s are just huge if you have limited desk space and - frankly - not that attractive.
Next I settled on buying two Gizmos and (unheard) two sets of Cambridge Audio (not Cambridge Soundworks) S30s. THey looked reasonably small and have lots of good reviews. They came yesterday - and when I unpacked them, the dimensions I had found online were wrong. They were bigger than I expected by about an inch each direction, which is a lot on a crowded desk. Still, I hooked up a pair to a Gizmo - and I hated them. The Gizmo is fine, but the S30s, without angled stands, are too directional and to me just don't sound good for near field listening. Also with desktop placement the rear-ported bass was really boomy, since I can't get the rear ports far enough from my office wall. They're going back.
So now that I have the Gizmos, what to do? Since it has a sub output with a fixed crossover, I'm pondering a couple of smallish inexpensive sub options (of course, if small as I want they're too pricey, and if cost-effective too big) with much smaller bookshelf speakers, like the Energy RC-Mini, the PSB Image B4 or the upcoming NHT SuperZero 2.0. Given the already sunk Gizmo cost, that is going to run me a total of at least $350 and likely more. Which is getting pretty damn close to the cost of the Exo2.
This is hard.