Hi there
I got my 2.0 Mb 15 inches MacBook pro one month ago.
It whines very very very seldom and as soon as some application like Photo Booth is launched, it stops until the next reboot (that can be in some days' time, as the system is very stable).
Coming from a 1.33 g4 17 incher, I can say that it is way more portable, light and responsive.
I do a lot of number crounching (with GNU R). The machine is rather fast. I hoped for something more, but it's ok. The dual core allows you to do real multitasking (R crounching numbers with one processor and the other one free for whatever you need to do).
A surprise: the fan is never turning. Compared to the g4, this machine is extremely quiet.