I went down that road long ago. Having a limited budget but still wanting to get the most for my dollar. Music is my primary focus. Made many mistakes along the way. There is good advice from many responding to your post. From all those responses I believe corelli has the most sound advice. Reason is...the heart of the system is the speakers and amp. The source certainly comes in after those.
The deals as far as cost in the used market are tempting and many great deals are to be had. However, don't underestimate the synergy of the amp and speakers. Some really good speakers and good amps may sound good but will they sound good together? That's the key. I've experienced that with expensive amps and speakers that didn't perform like a team.
If you go for the used market you are limited to the reviews of opinions from many but are not able to actually audition how they sound for yourself. That's where going to an audio dealer that may have the components you have interest in and will fit into your budget comes in. Audition amp and speaker combinations and decide what sounds best to you. If the dealer may also have the sources you prefer audition them as well.
Tweaks such as interconnects, power cords, room treatments, etc. can come later. You are looking for a good sounding system capable of what pleases you now. Good luck.
