I am sure its been covered but I couldn't find the thread....I know not all are created equal, and I didn't just spend money on a stereo to have the sound downgraded by a crap cable.

 

Aux cable could mean any number of things. At least specify the head unit you bought. If possible, identify what type of aux connection you have on your head unit.

Most are equal actually. It's the expensive "higher end" stuff with extraordinary claims that you really need to be leery of -- especially the stuff that's no better than coathanger wire (Google).

 

New alpine with HTC EVO phone, I guess a 3.5mm is what i want but......griffin, belkin, monster, .....???

 

If you want cables of the "highest quality", retail brands are not the way to go.
The brands you just mentioned are over priced. You'll only be paying for the name.
Just buy some gold plated cables from monoprice and call it a day. Never received a bad cable from them.

If you want learn more about cable wires: http://www.roger-russell.com/wire/wire.htm

All you really need to be concerned about is the wire size(AWG), the voltage from your device(ohm), and the length(ft).
There's a table for that here: http://www.roger-russell.com/wire/wire.htm#wiretable