Which is the most important part of a stereo system?


My system consists of a pair of B&W 630's, an old Denon 50 watt reciever (DRA-550) from the mid 80's, a Marantz CD5004 cd player, and now a Pro-ject Debut Carbon DC Turntable.  I'm pleased with the speakers and the cd player and while the Denon sounds good it has some issues and I want to upgrade.

I'm planning on returning the Pro-ject TT and getting a higher end TT.  I'm also looking into getting a new amp pre amp with a internal DAC.

Is the source the most important? The speakers? 

Please Help!
klimt
The SOURCE is the most important part of any audio system! The turntable/arm/cartridge for LP playback. For Digital it is the player (CDs) and DAC/transport. Music lost at the beginning can never be recovered later!
It's all important, but speakers are going to have the most impact on how the system sounds overall. 

I have someone coming to buy a pair of speakers today and after putting them in my main system so that I could dem them, the difference between my current reference speakers and those was quite noticeable. 

Putting a much more expensive turntable or CD player into my system wouldn't bring it back to the level it was with the other speakers.  Putting my Harbeths back in the system will restore it to its glory.