Building your own laptop is significantly more challenging than building your own desktop, so when it comes to laptops i suggest prebuilts.
What will she be doing with CS5? If she is going to be using premier and photoshop she will appreciate one of the quad core laptops that have an i7 and atleast 4GB of ram. Whats the budget for it and where can you buy from? Do you have any that you were looking at? We can advise you as to which one will be best.