Processors are on the path to Multi-Core whether our applications and games can handle it or not. I remember when I built my dual core AMD 6000+ and thinking this was my "Dream system", then a couple of years later updating my R2M5 to Quad. I don't yet have the desire to go to an i7 or a hexa-core, but I'm sure I will eventually.
At what point do you think you'll have enough cores?