Not always. It makes a difference in some areas, not others. The question needing to be answered is what will the notebook be used for?
This may be true, but the difference between a 5400 RPM and 7200 RPM hard drive is barely noticeable. Faster start up times may be provided and a faster copy and paste time, but only slightly. Whereas the processor has an effect on everything you do on a computer and speeds up just about everything. But i suppose if all the computer was going to be used for was storage of files the hard drive could be a better choice, but usually there used for games, movies and other uses.
The CPU has an effect on everything you do - but if the movies and such were limited by the HDD I/O, then getting a better CPU would have no effect. Upgrading the CPU will only make the machine faster if it's the limiting factor, which, in many cases upon loads of programs (which happens a lot) it is not.