The faster modem will speed-up data transmission and connections to the World Wide Web and online services. This offers a nice upgrade for an otherwise capable system that is running out of space. Average users will have a hard time filling a 1 gig drive. It can make future upgrades, like adding a modem, much easier. Prices for laptops are still at a premium, with some more than double the cost of a similarly configured desktop model.
Laptops are easier to lose, damage, and are stolen more often.
And, some keyboard styles are awkward for large hands. Unless you need mobility or a computer in three places, you may be better off with two desktop systems. On the other hand, the availability of CD-ROM and network interfaces may allow a laptop to be your only computer. Small LCD screens are limited for shared uses. Processors come in two different cabinet styles, desktop or floor-standing tower.