It really depends on how you will use your notebook. For me, storage space is more important than drive speed. For normal operations, you will see very little, if any, difference between 5400 and 7200 HDDs. In my use, I would much prefer the additional RAM as opposed to slightly more HDD speed that would be apparent in operations.
Transferring large files is more often than not constrained by the link used, and or the source moreso than the HDD. Example - if I am transferring digital images between my HDD and a USB Reader/Writer or camera, there would be no perceptible difference between a 5400 drive and a 7200 drive.
If you are a gamer, it might make a difference.