Hi Avguy; I have 5 20 amp dedicated outlets and consider them the foundation of my system. Because of the number of outlets needed, and the distance, I did have to go with a sub-main panel (with space for 8 breakers) from my main breaker box. The ded. line (to sub-main) comes off a 50 amp breaker in the main. The sub-main is fed by a 6 ga. stranded cable-- overkill I know, but I had it and it was pretty much in place.
My sub-main has 4 20amp breakers, and BTW, I tried using a box with glass fuses, but it really sounded excessively soft, dull, and boring. Redkiwi (A'Gon) member said ceramic was much better, but I couldn't find ceramic fuses.
I also had the sub-main grounded to 3 six ft. copper rods driven into the ground within a few feet of my ded. outlets. The main house ground is still active of course. I use 4 Hubbell audio grade outlets ( from www.fatwyre.com ), and one FIM (also 2 silver plated Acmes on speaker subs to nonn-ded. outlets). I replaced all stock power cords with good quality custom cords.
The benefits of this ded. system were huge, and initial cost was only $900. (not including power cords). Noise floor dropped dramatically, dynamics improved a lot, and silences (blackness) became much more silent. A good ded. system should imrove your existing system much more than an amp could. I had my system installed by a licensed electrician, and recommend that approach unless you're totally confident in doing the work yourself. Good Luck. Craig