The current core2duos the baseline iMacs provide are the fastest core2duos intel has on the market, so there's no chance in upgrading. Apple wouldn't upgrade to Clarkdales because they have to rely on integrated graphics, and apple would most likely want to have a lowest end iMac with top notch integrated graphics to appeal to their lower end customers. As it stands, 320m is fastest integrated chip on the market.
i feel that a 3.33 ghz maybe could be standard but most likely no so they can wait for the next next refresh when people hate the c2d for being to old and change to nehalem

apple is trying to transistion out of core as u saw with the mbpros, imac i5/i7, the mac pro and the xserve. all thats left that is the 13inch laptops and the macbook air (i dont see the point in it anyway). i agree with just another 3.06 ghz or A 3.33 GHZ bump in the imac 21.5 but i expect to see nehalem desktop dual core i5s a 3.2 ghz up there (i3s are only for dell type computers) since apple wants to make it about the price of the nehalems (3.2 ghz costs 196$$ or somewhere around there) the 27inch could see higher end dual core i5 desktops or maybe a quad core option. possibly the i7 could be standard again

as i have already said billiona of times. other than that, apple could be making their current high end offerings, their low end offerings.
to everyone else on gpus.. taking on the rumor that amd <3 apple, ati radeon chips could be discounted significantly. but apple has been sucking up to amd lately making new deals on amd gpus on their imac and if nvidia and intel start battling it out... we could see more powerful mobility radeon chips. as we can see difference between the mindset of nvidia (powerpowerpower!!) and amd (power with responsibility and management while owning nvidia and making an architecture that doesent toast a computer and take 100w tdp for a mobility gpu) amd gpu seems to have more sucess in terms of consumer perspective and buying. i would buy an 587- desktop for any frigin rig anytime as it runs cooler than most gpus at that level and its advanced

not like nvidia being to "i dont want to lose"