Phono cable - necessary?

I always thought a phono cable was only necessary if the turntable had a din connector that made use of a regular IC cable impossible so I never really paid much attention to phono cables as my VPI has the typical RCA box for the tonearm. Just recently my dealer told me that phono cables actually use special geometry and construction necessary to conduct the weak signal from the cartridge to the phono preamp properly. I felt flat out embarrassed that I was ignorant of that fact for so long. That said, what is the consensus among audiophiles on this issue? He recommended a Nordost Heimdall 2 phono cable, which at about $650 is certainly not cheap. I am looking to replace my current "phono" cable (Acoustic Zen WOW) as I don't like how thick and rigid it is, even though I really like it sonically. Any advice on the subject?