should be dropping to something like that, i've only read q2 so not sure of the april estimate and also takes a while for prices to trickle down as old stocks that cost more need to be sold.
but even at £320 2 cores will mostly go completely wasted, and often 3 cores.
one of, if not the only game that can use all 4 cores is supreme commander, and framerates are very cpu limited, dual/quad core makes like 5fps difference, ok its relatively large as we're talking like 40 up to 45fps, but in a game like that you're hard pushed to notice anything after you get to 25/30fps. not to mention thats on stock cpu speeds, if you whack a 6600+ up to 3.6Ghz its a different ballgame again.
i doubt you will find a game in the next two years(thinking non rts really) where both cores on a duallie are actually using 100% cpu power. by then quad core will be available at £100 in newer better chips with ddr3 and holodecks, ok, maybe not holodecks.