Nero,
It depends on what you plan to do.
If it's just for email, web surfing, watching DVDs, then get the laptop. You'll have the convenience of laying about in bed or taking it anywhere you fancy to go, such as the bookstore or library.
If you use it for any kind of gaming or production work, then get the desktop. For the desktop, you can choose the right sized screen for your work and eyes. For myself, I love a large screen and find laptops too tiny to read.
However, I have to do all my reading/surfing sitting in an uncomfy chair.
For most users, the laptop has plenty of power.
For most production work and gaming, you'll need the desktop.
Finally, with today's computer, you'll rarely need to ever go inside the machine... It's only handy when you want to add more ram/bigger hard drive, or better video card. Basically, the days of tinkering with a computer should be over, unless you're a geek like me.
If you're handy, buy the least amount of ram (memory). You can get ram much cheaper online. Email me if you need sites.
You can do a lot of pricing and specs by visiting
newegg.com, then compare it to dell and macs.
If you do get a desktop, don't overlook the importance of a good monitor. I have a 30" and it's great for browsing and watching DVDs.
Basically, if you have to be mobile with a computer, get the laptop.
If you're a home user, get the desktop.
If you like to do computing in bed, choose between the laptop or a desktop setup next to your bed.
If you must, absolutely MUST read email while on the potty, get the laptop.