by hikaru » Sun Apr 13, 2008 8:58 pm
It depends on what you have in your notebook now (CPU, RAM, HDD) and what you are doing with it.
I found a configuration with 2,4GHz CPU, 256MB RAM and 40GB HDD. If you have a similar configuration, then I would recommend you to upgrade your RAM. This will have the best effect with the lowest price.
If you are out of disk space, then a bigger HDD will be positive too. But you should also think about external HDDs since the price per GB is lower and you can still use it, even if you decide to buy a new notebook.
A CPU-upgrade doesn't seem to be wise to me.