Casey, there's some good stuff on that list. But I would start with the Cambridge Ensemble system -- it's good and you can't beat getting it for free. I never heard the Ensemble II, which I believe is a scaled down system with one bass unit instead of two, but the original Ensemble had a very sweet midrange, decent bass and a somewhat soft and rolled-off treble that was perfect for smoothing out the rough edges of cheaper CD players and amps -- which should work well in your situation. Another plus is your placement options will be greater than with a regular box speaker. Yet another plus is you'll be able to get away with cheap speaker wire by the spool and any decent $10 interconnect between your CD player and amp.
Now you can save your money for a few years and enjoy quality music while slowly upgrading. I think the best upgrade path for you would be to look into a new integrated amp when your budget allows -- something in the $500 or less range from Cambridge Audio, NAD or Rotel would be a good start. Then look into a good CD or universal DVD player, which are going very cheap these days, around $200-$400 and much less than that on the used market. And finally, a nice set of speakers, also in the $500 range.
With a more powerful and higher-res integrated amp, you'll hear an improvement in bass grip and midrange focus with the Cambridge speakers, especially if they have a passive (non-powered) bass unit, which I suspect they do.
The new CD or DVD player will enhance the resolution even more.
Finally, when you add the new speakers, the whole system will take a huge leap forward.
If you upgrade the speakers now, you won't hear what they're fully capable of. If you upgrade the disc player now, the amp you have probably won't let you hear an improvement. But if you follow the amp-CD-speakers path, you'll be in nice shape and you'll enjoy every improvement along the way.
