I've read about the virtues of point to point wiring of amps in many articles and plan to build my power amp this way. What would be the most approprate wire to use? I 've read somewhere in the forums that the best is tin plated copper wire without insulation; is it true?
Use a thick wire as practicle and/or possible. Tin plated looks maybe nicer but meens nothing in electrical terms. Can be easier to solder but fresh copper is also easy to solder if you regular solder tin with flux inside is used.
The coolest wire is teflon isolated!
Don't forget to have as short wires as possible. Pcb's are often better because of the possibilty to have ground planes with makes the amp less sensitive to EMI and overall get a better performance due to low impedance ground.
I forgot: The coolest wire is of course one made of silver!
Personally, I would suggest that rather than using wire, as much as possible you use the component leads. Solder joints definitely degrade the sound, and their number therefore should be minimized.
In general, I also agree that short connections are good, but you may also want to think about the effect of induced magnetic fields on the surrounding components and circuit nodes (just like you would when constructing a loudspeaker crossover).
Check my thread here http://www.diyaudio.com/forums/showthread.php?s=&threadid=3840 to see how I wired Aleph X. For rails I like to use 14 ga. solid copper wire used for in wall AC installations. I also use the components leads whenever possible. I like Kimber 19ga wire for signals and 14 ga wire for high current. I don't take the insulations off, but heard it improves sonics. Recently started to use silver wire, because I bought it cheap.