Goertz still the choice with Vandersteen?

AudioQuest great performance and avoid the above which Almarg notes.
JohnnyR Vandy dealer

Yup, listen to Johnny. He's the best in the country, other than Mr Vandersteen in setting them up. He sells the AQ's with them because he knows how neutral they are and how great they sound together. All of us who own the Vandy's have posted about using AQ and we do it for a reason. Also, keep the runs as short as possible. Less than 8' will sound best if you are able to set your system up that way. Most any of their DBS cables will sound awesome.

Keeping it simple is usually best. Let us know what you will do.

Goertz sounded awesome for the bass, I find that they don't sound quite right for the high frequencies though. DIY silver cable is the way to go there.

AQ is one of the most neutral out there and that's what a properly built and designed speaker needs. Vandersteen's fit that bill (as do others). In speaking with an audio engineer/designer, he said that he's had many of the top named cables on his bench and many couldn't even pass a square wave. They clipped them and it didn't matter what materials were used, they just weren't designed properly. Two of the four important things to think about with cables are:
1. can they pass a square wave
2. will they keep the time alignment between all frequencies.

The problem with any DIY silver cable that folks talk about is that you are getting your wire from someone else so that means you don't know how it was drawn and handled. That's a major problem with silver wire. If silver isn't worked properly, you will get what we in the 90's said was a hot wire. It can sound amazing if used correctly, but very few DIY's can work it properly and that also means consistently as they just aren't set up for it.

There are plenty of cables that sound awesome in one aspect, but not in another and that ruins the sound of great components. You are dealing with different needs between frequencies, so a company that gets bass right and isn't getting mids AND highs correct makes no sense if you are trying to max out your speaker purchase.

JMHO

In speaking with an audio engineer/designer, he said that he's had many of the top named cables on his bench and many couldn't even pass a square wave. They clipped them and it didn't matter what materials were used, they just weren't designed properly. Two of the four important things to think about with cables are:
1. can they pass a square wave
2. will they keep the time alignment between all frequencies.

I'm not sure what that designer was trying to say when he exclaimed that many of the cables on his lab bench could not pass a square wave??? Can you explain his comment since it seems you had a 1-1 conversation with him?
Music is not square waves by any stretch of the imagination.
So, what's with the not passing a square wave correctly?
One thing I can imagine is that he was checking the slew rate capability of the cable. If not designed correctly, the slew rate could have been messed up due to higher parasitic capacitance. Also, if there is more inductance in the cable that could form a LC low-pass filter & limit the high freq content the cable could carry. Do you think he was checking this for those cables on his lab bench?
I don't think that cable can keep the time-alignment amongst various frequencies but i think that it could keep the phase relationship amongst the various freq. Time alignment would become a factor for a loudspeaker where time is required for the sound from the various drivers to integrate correctly at your listening position.
But, yes, extra C &/or L can definitely mess up the phase relationships of the frequencies in the music signal traveling thru the cable & that in turn could mess up sonics thru the speaker.

The problem with any DIY silver cable that folks talk about is that you are getting your wire from someone else so that means you don't know how it was drawn and handled.

Nah! I dont agree that this is the principal limiting reason for making one's own DIY silver cable. A better supplier for DIY can always be found - you might not like the price but it can be found. The manuf definitely didn't know any better who drew their bulk silver cable - they were just as clueless. If you are going to tell me they knew who & how their silver cable was drawn then I'll have to say that you are quite naive. Search the archives - there are 100s of cables from many, many manuf which were deemed "hot wires" by the users.
I think that the principal reason for not doing one's own DIY cable is that one does not fully understand how to keep the finished cable low capacitance & low inductance, retain the phase relationship of the music signal as its passing thru the cable, termination - as in impedance of the finished terminated cable so that it's correct for the intended use, etc.

You are dealing with different needs between frequencies, ....

I don't think so! The needs for all the frequencies remains the same - make the cable low capacitance, keep the resistance portion as small as possible, keep the parasitic inductance to a minimum.
This was already alluded to by Almarg.

if you want to read a really nice thread on cables, read this one - many good contributions in this thread:
http://forum.audiogon.com/cgi-bin/fr.pl?fcabl&1363313104