If you feel the c2d is "very underpowered" you're going to want to go with a REAL quad core i7. The new dual cores are nice but honestly, it's only few seconds faster when it comes to CS work. It would help tremendously with HD movie work but I can't imagine it's anything very serious.
I have a MBP and a ipad now and I find myself using the mbp less and less on the go. For notetaking and browsing the ipad is just much, much better.
If I could do it again I would personally get a decked out iMac+iPad.
But, the C2D I am using currently is a mobile C2D clocked at 2.13GHz, with a frontside bus of 800MHz. I believe the iMac (currently) has a Desktop Core i3, clocked at 3.2GHz, with four threads, and don't the new processors use a new bus??? Anyway, I will be buying an iMac once they are available with Sandy Bridge, since I am in no hurry... And yeah, I Think I should get an iPad 2G before I get an iMac or MacBook Pro...
Thanks.