I tend to agree with Redkiwi and Sedond's seconding on this one. Neutrality is the ideal goal. That said, you may want to ask yourself this question. "Do I want the best system possible, realizing the cost and effort may be prohibitive, or am I happy with a very nice sounding system that I enjoy." Neither answer is right or wrong. I think many times we lose touch of the practical in looking for the ideal. If you are looking for an enjoyable, not too expensive option, read along. I had a similar set up with similar findings as you when I started this audio thing many years back. I had an A150 as well and a similar qualtiy CD player. What made a big difference for me was to buy a CAL Icon MKII- used around 400 back then. I think they would be less now. It was a very pleasant addition to the Acurus at a reasonable price. It was a marked improvement over the very thin/tinny sound of my previous CD player. (BTW- that's what I think the weak link in your system is- I think you have already figured it out by your posting). Once I began significant improvements in other components, the CAL left my system for seperates.
If you think you want to spend time building your system piece by piece and experimenting, then the CAL may still be a good deal, as it will probably hold its value if bought used. If you are searching for true audio nirvana, the "as near as possible to the live event", I cannot more stongly agree with Redkiwi's post. Try to get neutral components. Just realize the slippery slope many of us (myself included) are headed down. (Albeit an enjoyable trip).
One more thing Redkiwi alluded to. Room acoustics: If your room has alot of glass, hardwood floors, framed art (with glass), or a lack of soft furniture, this makes a VERY big difference in the sound , turning the sound bright. There have been a lot of threads on room acoustics in the past, done much more eloquently than I can, so check them out. Alot of tweaks in this realm are cheap, and many are visually pleasant as well. That aside, I still think the CD change will help alot. Best of luck and happy listening.