The biggest challenges are expandibility and upgradeability. I am currently usng my Sony VAIO laptop, however it is my main computer for both work and personal. It is a year old, has a PII/333, 128 MB RAM and a 6.4GB HD. I can only dedicate about 1.5GB to MP3s, giving me about 530 songs. My CD library alone has over 7,000 songs, most of which I would like to rip. Upgrading the hard drives in laptops is nowhere near as easy as with convetional desktops, they cost more to begin with, so even used they are more expensive, and they use a lot of proprietary parts, making them even more difficult to upgrade. They are great for what they can do, but building a machine from convetional desktop parts allows for greater flexibility at a lower cost.