City dweller power cable & conditioner questions

I have a simple set up with a Unico integrated, turntable, and (soon) Squeezebox. I'd like to change the stock power cable for the Unico, but I'm not sure what the best way to do it would be. The units are about 10ft away from the nearest outlet, and right now I'm just plugging everything into a regular old surge suppressor--which buzzes annoyingly. I also get occasional interference from what sound like taxi cab radios (or could that be coming through the unshielded speaker wire?). I live in an apartment in NYC. I've read conflicting things about plugging the amp directly into the outlet vs. using a conditioner. What would you advise? Is it worthwile or necessary to "condition" city power? My budget is only about $300.