I have a laptop and a desktop and wouldn't want to give up either of them. I use them both for different purposes. The laptop is great for portability and mobility, ie. I can browse the web throughout my house, or take it to libraries when I'm at Uni.
But it's not as comfortable to use as my desktop nor as powerful, especially in the graphics department. I know you can buy laptops with powerful graphics cards and desktop-equivalent CPUs, but they're hot, heavy and the batteries last about an hour. I want my laptop to be a laptop, not a 'desktop replacement' which is jack of all trades but master of none. I can't fit a laptop with 17-inch screen and Geforce 7900 in my rucksack. Thus I'll keep my desktop for performance.