Well, here is my newbie system. Put together on a budget, almost every piece was bought used. Actually "preowned" sounds better. The tonearm and cartridge were new. Now I guess that I am in tweak mode, my next purchase will be some kind of power conditioner, and some vibration/isolation devices of some sort. My room is over the garage, so its a suspended floor. The TT is sensitive to noise in the room (usually my 4-yr old child), so I've got to work on that. Also I have a pesky ground loop hum through the TT that needs work. Please comment on my stereo or offer any advice on how to improve it without breaking the bank!
I agree that power conditioner(s) would be a good step. What sonic deficiencies do you feel you need to address with upgrades? What are you not getting with your present setup?