Best Type of Automotive Wire

[Spool]

-100% copper
-Aluminum Clad
-Copper/Tin

Is one type of wire more superior to another?

I'm looking to buy quite a bit, and the prices were far cheaper than I anticipated. 

[bd]

Use stranded, 100% copper wire jacketed in GXL or SXL rated insulation (cross-linked polyethylene).  Tin plated copper wire is more for marine applications and similar corrosive environments.

See:  "What's everybody's favorite source for buying wiring/looms/etc.?"

[Spool]

Great info and link! Thanks, BD.

[75gmck25]

Also remember that the wiring you find on the shelf at Autozone and other parts store will usually not have very durable insulation, so it will not hold up like OEM quality wiring. 

You can get an idea of how the insulation holds up by flexing the off-the-shelf wire - it is extremely flexible, and you can probably pull the insulation apart with a couple of pliers.  The lower grade insulation works find for under the dash or other areas that are well protected, but its not a very good choice for under the hood, running trailer lights. etc. where its subject to more heat and road damage.

Bruce