I really hope Apple move a bit faster than this and adopt Nehalem sooner rather than later - I didn't even know that there was any more speed bumps planned / available for the Core 2 Duo chips?
In my ideal World we'd see the Clarksfield chip installed in the iMac by final quarter of 2009 - a good way for Apple to cross promote the advantages of Snow Leopard and multi core processing. Wether this will happen due to perceived heat issues and and wether Apple probably having to take a processor clock speed reduction in adopting the mobile Clarksfield chip, is anyones guess.