i am planning to get myself an imac, but i dunno whether to get a quad or duo core version.

Based on my research, core 2 duo is going to be replaced by i3 or i5 in the near future. So getting a quad core seems to be better, but the thing is, this mac will only be used in this few years time, and can the quad core being fully utilize within this period? since there is not much app utilize multicore.

so, i5 or core 2 duo?