Which is better longer xlr or speaker cable

Second samhar's advice. I use SilverBlue from Audio Synthesis which was reasonable when I bought mine and came with WBT plugs but bought it a long time ago.

Short speaker cable is best if you have XLR. Mogami (owned by Marshall) make good quality XLR.

Agreed that it's an advantage to have short speaker cables(still go with the best you can afford). Don't for a minute believe that, "the quality of the IC doesn't matter as much with balanced cable"! We're discussing a complex musical signal here, not the input of one microphone or instrument. At VERY LEAST: go with Mogami cables (http://accessories.musiciansfriend.com/product/Mogami-Gold-Stage-Mic-Cable-with-Neutrik-XLR-Connectors?sku=338011), which are built with oxygen free copper, polyethylene dielectric and use Neutrik XLRs. If you skimp on your interconnects: You WILL lose a lot of musical information. If the rest of your system is accurate/resolving, and you do a comparison between pro and high-end balanced cables: The differences are quite audible. Of course everyone doesn't have the same aural acuity, or knows how to listen for differences. Consider how big Stereo Review's readership was(compared to any of the high-end magazines), and it's primary reviewer never heard a difference in anything(in thirty years of writing). Keep the speaker cables lengths short as possible, and you probably won't notice a difference between bi-wired and not(with good jumpers). It's best to keep all cable lengths as close to equal as possible, but don't neatly coil anything, and don't run any power lines parallel to your signal cables(not within 8in anyway). Happy listening!

Bettercables.com is also a great resource for reasonably priced longer balanced cables.