Shorter speaker runs or shorter IC Runs...Which is the better set up and why?

Longer speaker wire (unless talking >50ft) only effect wattage loss and lower damping factor, which can be negated by using a thicker gauge.

Longer interconnects do have worse crosstalk and jitter (if talking digital), but a good DAC should take care of the latter and crosstalk has to be immensely bad (above -40dBFS) to be noticeable, which I don’t even think a 50ft RCA would have audibly poor crosstalk; but frequency response, THD, IMD, etc. are almost always near identical to a short interconnect.

@mzk,
The OP stated he is using XLR cables. Length will have no impact on sound.

Longer speaker wire (unless talking >50ft) only effect wattage loss and lower damping factor, which can be negated by using a thicker gauge.

I disagree totally. How the cable is designed, what materials, etc. contribute to how they will reproduce sound.
B

@gdnrbob

No, what materials being used has no negation that the only difference is loss in wattage and worse damping factor. You could say a better speaker cable has better EMI rejection, but then you are assuming you live in an environment with heavy EMI. 

Also, sorry to burst bubbles, silver is only better than copper in one way, it conducts electricity a bit better, meaning less wattage loss for the same distance, but 12awg copper conducts electricity much better than 14awg silver, so the premium of silver is not worth it.

Ok it definitely looks like the short run speaker cables win!  Now for a (albeit entry level) follow up question.  When connecting the PreAmp to the Amp VIA XLRs should I opt for equal lengths of XLRs or just the shortest?  As example:  The preamp will be approximately 4 feet from one amp and say 13 feet from the other so should I do 2 lengths of 14 feet or 1 of 4 and the other of 14 or both 14?  Both the amp and preamp are balanced...Thanks!
 

XLRs when used in a truly balanced system are generally zero signal loss and low distortion, and some do sound better than others, but generally not by much (many decades of live sound work taught me this). So if balanced cables come in pairs, simply get what fits and yer done, and don't worry if one cable is too long as placement of your stuff can change. Shorter good speaker wires can save some bucks.