[Irwin]

Lets say you're happy with your budget rig,Amplification,Source and Speakers.What Cheap and Cheerful piece of gear would you add to your system.$100 maximum,new or used?

[BobRex]

MUSIC!!!!

[Letitroll98]

DIY room acoustics treatments.

[decal]

MUSIC!!!!

Ditto (theoretically)!!!!!!!!!!!!

[neekomax]

9 months of Spotify Premium (320 kbps streaming, mobile app [ROCKS!]), and then buy Airfoil software with the remaining money (streams any computer audio to whatever airplay device).

-OR-

Apple TV ($99), awesome streaming device, plus all the video stuff to boot.

Did I mention I enjoy streaming? 

[Ericus Rex]

A nice and comfy chair.

[underdawg]

accoustic treatments and music , maybe some isolation or dampening to.

[geowak]

If you have an IPHONE, I'd look at the Pure I-20 dock. Great internal DAC and start streaming music from your phone to hi-fi system!!
I have MOG and love the app MOG has for IPHONE.

[konut]

The upscale booze of your choice.

[rooze]

Depending on the rig and where you're at with the sound, I might add a tube buffer between CD player and amp.

Or, perhaps an external DAC to lift the performance of CD's.

I suppose you could find either one of these used if you shopped around..

[SteveFord]

Headphones.